John Isner is fresh off the biggest title of his career, as the 32-year-old became the oldest first-time ATP World Tour Masters 1000 champion when he triumphed at the Miami Open presented by Itau last weekend.

Now, it’s on to the next challenge for the American — Isner will have to immediately dig into the red clay of the River Oaks Country Club as he seeks his second tour-level clay-court title, and his second in Houston at the Fayez Sarofim & Co. U.S. Men’s Clay Court Championship.

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“It’s up to me now to keep pushing forward,” Isner said after his Miami victory. “This is a big hurdle for me, mentally more than anything, to get over the hump in a tournament like this.”

And it may not be long until the top seed faces a stern challenge in Houston, which is the right-hander’s home event — he now resides in Dallas. The World No. 9 will face German Dustin Brown or Swiss Henri Laaksonen in the second round. Isner lost against Brown in a third-set tie-break in Houston four years ago when he was attempting to defend his 2013 title.

Past Five Houston Champions

But Isner is not the only American seeded at the only ATP World Tour clay-court event in North America. He is projected to face sixth-seeded compatriot Steve Johnson in the quarter-finals for the right to potentially play No. 3 Jack Sock or No. 7 Ryan Harrison in the semi-finals.

Harrison became the youngest player — and remains so — to win an ATP World Tour Match since Rafael Nadal (2002 Mallorca) at 15 years old in Houston 10 years ago, qualifying before defeating Pablo Cuevas. The American, who advanced to the Brisbane final earlier this year, makes his return to Houston for the first time since that breakthrough when he faces a qualifier in the first round.

No. 2 Sam Querrey, a runner-up at this event in 2010 and 2015, will open his campaign against Argentine Guido Pella or a qualifier. No. 8 Tennys Sandgren joins Querrey on the other half of the draw.

One of Querrey’s potential semi-final opponents is making his debut in Houston — third seed Nick Kyrgios. The Australian, who is one of two players to have beaten Rafael Nadal, Roger Federer and Novak Djokovic in their first FedEx ATP Head2Head meetings (Lleyton Hewitt), will open against compatriot Jordan Thompson or American Bjorn Fratangelo.

Read: After Three Months, Americans Top ATP Race To Milan

Two #NextGenATP Americans who have gotten off to fast starts in 2018 will look to continue their good form. Frances Tiafoe, who at the Delray Beach Open became the youngest American to win an ATP World Tour title since Andy Roddick at 2002 Houston, will look to back up his Round of 16 appearance in Miami with a first-round win against wild card Mackenzie McDonald. Taylor Fritz, 20, who achieved his best Masters 1000 result by reaching the fourth round at the BNP Paribas Open, takes on compatriot Tim Smyczek. 

SPAIN 1, GERMANY 1
Venue: Plaza de Toros de Valencia, Valencia, ESP (clay- outdoor)

World No. 1 Rafael Nadal returned to action for the first time since the Australian Open on Friday, beating Germany’s Philipp Kohlschreiber 6-2, 6-2, 6-3 in Valencia.

The Spaniard hit 28 forehand winners throughout the two-hour, 33-minute clash at the bullring venue to score his 23rd consecutive Davis Cup singles victory and level the tie at 1-1. “It’s positive of course, winning in straight sets,” Nadal told DavisCup.com. “It was a solid match. I feel comfortable back on the clay.

”It’s always special to play at home at a bullring stadium, it’s very unique. It’s a great feeling to be back, coming back from injuries is always difficult, but it’s great to be in front of my crowd on a very memorable day. I’m very happy with the match.”

Nadal was under pressure to deliver a crucial first point for the home side after Alexander Zverev secured the opening point of the quarter-final with a convincing 6-4, 6-2, 6-2 win over David Ferrer.

Despite dropping serve on five occasions, the World No. 4 broke the Spanish veteran 10 times to earn three-time champion Germany an early lead in eastern Spain after one hour and 55 minutes. The Miami Open presented by Itaú finalist moves to 3-0 in 2018 Davis Cup play after wins over Australia’s Alex de Minaur and Nick Kyrgios in the first round.

“I am just happy to get the result,” said Zverev. “I played more aggressively as the match went on. It is my first clay-court match in a very long time so it was great to find my rhythm so quickly.”

Germany is bidding to become the first team to beat Spain at home since Brazil in 1999, with Spain winning its past 26 ties on home soil.

ITALY 1, FRANCE 1
Venue: Valletta Cambiaso ASD, Genoa, ITA (clay – outdoor)

Lucas Pouille withstood a strong comeback effort to beat Italy’s Andreas Seppi 6-3, 6-2, 4-6, 3-6, 6-1 in Genoa.

The World No. 11 began well, breaking six times en route to a two-set lead, but Seppi fought back in front of his home fans to force a decider. Not to be denied, Pouille re-established control and raced to victory in the fifth set to secure defending champion France a 1-0 lead.

“The emotions are the maximum,” Pouille told DavisCup.com. “It’s great to win that type of match. I was two sets up, he came back; that was so tough for me in the fourth set. I tried to fight as hard as possible and in the end I decided to be more aggressive and I was very happy at the finish.”

Fabio Fognini levelled the tie at 1-1 going into Saturday’s doubles rubber, coming from a set down to beat Jeremy Chardy 6-7(6), 6-2, 6-2, 6-3.

The Italian won 70 per cent of points behind his first serve in the three-hour, 31-minute encounter to improve to 15-2 in Davis Cup singles rubbers on clay. Simone Bolelli and Paolo Lorenzi are scheduled to meet Pierre-Hugues Herbert and Nicolas Mahut on Saturday.

CROATIA 1, KAZAKHSTAN 0
Venue: Varazdin Arena, Varazdin, CRO (clay – indoor)

Marin Cilic began Croatia’s bid for a second Davis Cup World Group semi-finals appearance in three years with a dominant 6-2, 6-1, 6-2 win over Dmitry Popko.

The World No. 3 looked in fine form throughout the one-hour, 41-minute contest hitting 32 winners past the Kazakh to seal the first rubber in emphatic style. Cilic, who led Croatia to the Davis Cup final in 2016 (l. to Argentina), improves his Davis Cup singles record to 25-10.

Kazakh No. 1 Mikhail Kukushkin upset in-form Borna Coric 3-6, 7-6(5), 6-4, 6-2 to end Day One with the teams tied at 1-1. Kukushkin broke the BNP Paribas Open semi-finalist on five occasions on his way to victory after three hours and 32 minutes. Ivan Dodig and Nikola Mektic are slated to meet Timur Khabibulin and Aleksandr Nedovyesov in the third rubber doubles on Saturday

With 33 tournaments in the books, the ATP Challenger Tour season is already off to a flying start in 2018. Storylines abound on the circuit, as new names and fresh faces fight for position in the ATP Rankings, while the Next Generation of stars look to make early statements in the ATP Race To Milan. 

Players eyeing coveted berths in the Next Gen ATP Finals lifted trophies, a superstar kicked off his comeback, a trio of emerging stars tasted victory for the first time, the Aussie contingent made an early statement, a 37-year-old veteran earned a historic crown, and a fan-favourite tournament celebrated a milestone anniversary. And of course, there were Hot Shots. Your jaws might still be on the floor.

In case you missed a moment or just need a refresher, here are the eight biggest storylines from the first quarter of the 2018 season on the ATP Challenger Tour…

The Youth Movement Continues
Two #NextGenATP champions, two teen finalists and four players aged 21 & under among the Top 10 in match wins… It has been a strong first quarter of 2018 for the future of pro tennis, as the stars of tomorrow continue to make strides.

Taylor Fritz and Marc Polmans, both aged 20, led the #NextGenATP contingent with titles on home soil in Newport Beach and Launceston, respectively. For Fritz, it was a long-awaited return to the winners’ circle. The former World No. 53 returned to the Top 100 with a vengeance, claiming his first title in two years. Polmans, meanwhile, lifted his first Challenger trophy. The Aussie is currently eighth in the ATP Race to Milan.

Germany’s Daniel Altmaier and Spain’s Nicola Kuhn turned in the best results among teenagers. Altmaier reached his first final in Burnie, Australia, while Kuhn finished runner-up on the indoor hard courts of Budapest. The 18-year-old has since notched his first ATP World Tour victory at the Miami Open presented by Itau.

Other emerging stars include 21-year-olds Hubert Hurkacz, Matteo Berrettini and Christian Garin, who, along with Fritz, are Top 10 in Challenger match wins.

Five Things To Know About Hubert

Mats Moraing, Ladies and Gentlemen…
Not even Mats Moraing could have believed what he’d accomplish in the first three months of 2018. 

After starting the year at No. 274 in the ATP Rankings – with just six Challenger match wins to his name – the 25-year-old made a massive splash with a 19-7 start. He would claim his maiden Challenger title at home in Koblenz, Germany, just weeks after reaching his first final in Bangkok as a qualifier. Moraing also made a major statement with an upset of former World No. 6 Gilles Simon in Cherbourg, France. 

Up to No. 156 in the ATP Rankings, the German joins Polmans and Gregoire Barrere as first-time winners this year. As he makes the transition to full-time status on the ATP Challenger Tour, Moraing is one to watch as the year progresses.

Five Things To Know About Mats

Kei’s Comeback: Nishikori Returns In Newport Beach & Dallas
In an era where big stadiums and mammoth arenas dominate the sporting landscape, witnessing the greatness of a superstar in an smaller, more intimate setting still holds a special charm. That’s exactly what fans in Newport Beach, California and Dallas, Texas experienced when former World No. 4 Kei Nishikori kicked off his comeback from a wrist injury at the Challenger events. 

In arguably one of the biggest player appearances in the history of the ATP Challenger Tour, fans came out in droves to witness the Japanese superstar in action. After falling in his opener in Newport Beach, he would drop one set en route to the title at the T Bar M Racquet Club in Dallas. 

Aussie Contingent Makes Early Statement
The nation of Australia has dominated the early stages of the 2018 season, with five different players lifting five trophies. Marc Polmans was the lone first-time and #NextGenATP winner of the group on home soil in Launceston. Jason Kubler’s comeback campaign continued, as the Brisbane native returned to the Top 200 for the first time since 2015, on the heels of his victory in Playford. 

Another Brisbane native also continued his comeback from injury, as John Millman triumphed in Kyoto, Japan, less than one year removed from undergoing groin surgery. He is back in the Top 100 of the ATP Rankings at No. 89. After stepping away from tennis for nearly a year, Alex Bolt made a splash in his return, emerging victorious in Zhuhai, China. And Sydney native Jordan Thompson also returned to the winners’ circle with his win in Chennai, India. 

With teen sensation Alex de Minaur also surging up the ATP Rankings and Alexei Popyrin making the transition from juniors, Aussie tennis is enjoying a wealth of success on the ATP Challenger Tour.

Taking The Next Step
Making the transition to the ATP World Tour is the goal of every player competing on the ATP Challenger Tour. For some, it comes faster than others. With just one year of Challenger experience, De Minaur made a splash at both the Brisbane International presented by Suncorp and Sydney International, reaching his first ATP World Tour semi-final and final.

He joined Nicolas Jarry and Felix Auger-Aliassime as emerging stars enjoying initial success at the tour-level this year. After claiming three Challenger titles in 2017, 22-year-old Jarry streaked to the semis in Rio de Janeiro and also reached his first ATP World Tour final a week later in Sao Paulo, en route to a career-high No. 61 in the ATP Rankings. Meanwhile, after winning a pair of titles last year, Auger-Aliassime qualified for his first Masters 1000 event in Indian Wells and reached the second round. The 17-year-old became the youngest to win a match at the BNP Paribas Open since Michael Chang in 1989.

In addition, Matteo Berrettini and Mirza Basic became the lone players to make Top 100 debuts in 2018. Basic and Roberto Carballes Baena are Challenger stalwarts who lifted their first ATP World Tour trophies, in Sofia and Quito, respectively. American Tennys Sandgren enjoyed a dream run to the Australian Open quarter-finals after battling in Challengers for nearly seven years. 

Dallas Celebrates 20th Anniversary; Oracle Series Debuts
It was a dream week for the RBC Tennis Championships of Dallas, as Kei Nishikori helped celebrate the tournament’s 20th anniversary. One of the longest-running indoor tournaments on the ATP Challenger Tour, the T Bar M Racquet Club first opened its doors to the tournament in 1998. 

Meanwhile, the Oracle Challenger Series debuted to rave reviews in Newport Beach and Indian Wells. The $150,000 events in Southern California were a hit among players and fans. With a total of eight tournaments on four continents making their debuts, others included Punta del Este, Uruguay; Lille, France; Marbella, Spain and Qujing, China.

Robert Joins An Exclusive Club
As the saying goes, ‘You are only as old as you feel’. In that case, Stephane Robert feels pretty amazing. At 37 years and eight months, the French veteran became the second-oldest champion in ATP Challenger Tour history when he lifted the trophy in Burnie, Australia in early February. Only a 38-year-old Dick Norman was older when he triumphed in Mexico City in 2009. Moreover, the victory made Robert the only player to win multiple titles over the age of 37, having also prevailed in Kobe, Japan last year.

Hot Shots, Oddities & Marathon Rallies
The #NextGenATP contingent turned in some of the most jaw-dropping and mesmerising ‘Hot Shots’ from the first quarter. From Alexei Popyrin’s tweener pass to Hubert Hurkacz’s tweener lob, as well as Corentin Moutet’s rifled forehand in Saint-Brieuc, Alex de Minaur’s stunning dig in Irving and Mikael Ymer’s stab volley in Rennes, the teens were well represented. 

Filip Peliwo, Roberto Quiroz and Christian Garin earned top honours for January, Feburary and March, respectively, while Aliaksandr Bury and Hsien-Yin Peng earned the most improbable of Hot Shots with a winner off the post in their Qujing doubles final.

ATPWorldTour.com previews this week’s four Davis Cup quarter-finals, which feature three of the Top 4 players in the ATP Rankings.

SPAIN v GERMANY
Venue: Plaza de Toros de Valencia – Valencia, Spain
Surface: Clay (outdoors)

Five-time champion Spain welcomes back World No. 1 Rafael Nadal for the first time in the competition since September 2016 in its 17th meeting against Germany, the 1988-89, ’93 titlist. Germany leads Spain 10-6 overall, but the two nations are 4-4 in clay-court ties. Spain has won 26 straight home Davis Cup ties, with its last defeat at home coming against Brazil in 1999.

Nadal, who has not played since falling to Marin Cilic in the Australian Open quarter-finals more than two months ago, has won 22 consecutive singles rubbers since losing on debut in 2004 against Jiri Novak of the Czech Republic. The lefty is joined by Pablo Carreno Busta, Roberto Bautista Agut, David Ferrer and Lopez.

As Spain looks to reach the semi-finals for the first time since 2012, Germany’s last semi-final came in 2007. World No. 4 Alexander Zverev, the recent Miami Open finalist, contests his fourth tie alongside Philipp Kohlschreiber, Jan-Lennard Struff, Tim Puetz and Maximilian Marterer.

The winning nation meets Italy or France.

ITALY v FRANCE
Venue: Valletta Cambiaso ASD – Genoa, Italy
Surface: Clay (outdoors)

Italy, the 1976 champion, contests its 250th Davis Cup tie this week, against defending champion and 10-time titlist France for the first time since the 1996 World Group semi-finals. The two nations are tied at 5-5, having first met in 1911.

Fabio Fognini, who has competed for Italy every year since 2008, plays alongside Paolo Lorenzi, Andreas Seppi, Simone Bolelli and Matteo Berrettini. Lucas Pouille, who won the decisive fifth rubber in the 2017 final against Belgium, headlines for France alongside Adrian Mannarino, Richard Gasquet, Pierre-Hugues Herbert and Nicolas Mahut.

Italy has lost just one of its past seven home ties, while France has won its past five ties. France’s best winning streak was eight consecutive ties between 2000-2002.

UNITED STATES v BELGIUM
Venue: Curb Event Center – Nashville, TN, United States
Surface: Hard (indoors)

United States, the 32-time winner, aims to extend its 4-0 record against Belgium, the 1904, 2015 and 2017 finalist, and one of the most competitive nations in recent years. It will be first clash between the two nations since the United States recorded a 4-1 victory in 1998 at Indianapolis.

John Isner, currently a career-high No. 9 in the ATP Rankings, competes straight off from winning his first ATP World Tour Masters 1000 crown at the Miami Open. With a 14-11 record in ties, Isner is joined by Jack Sock, Sam Querrey, Ryan Harrison and Steve Johnson as the United States attempts to advance to the semi-finals for the first time since 2012.

Belgium, without its leading player David Goffin, bids to reach the semi-finals for the third time in four years with Ruben Bemelmans, Joris De Loore, Sander Gille and Joran Vliegen. The nation has lost just one of its past eight hard-court ties.

The winning nation meets Croatia or Kazakhstan.

CROATIA v KAZAKHSTAN
Venue: Varazdin Arena – Varazdin, Croatia
Surface: Clay (indoors)

Croatia, led by World No. 3 Marin Cilic, bids to reach the semi-finals for the second time in the past three years in a first-time meeting against Kazakhstan.

Cilic, Borna Coric, Viktor Galovic, Ivan Dodig and Nikola Mektic will look to extend Croatia’s five-match winning streak on clay, but the 2005 champion has lost five of its past seven ties.

Kazakhstan, competing in the World Group for the seventh time in the past eight years, will look to Mikhail Kukushkin in its attempt to advance to the semi-finals for the first time. Kukushkin, with a 22-13 event record, is joined by Aleksandr Nedovyesov, Dmitry Popko, Timur Khabibulin and Denis Yevseyev.