Three-time champion Juan Martin del Potro’s Citi Open winning streak is up to 15 matches with the Argentine taking down Lukas Lacko on Tuesday night. The No. 13 seed downed the Slovak 7-5, 6-2 as he advanced to the third round.

The 28 year old will carry a 5-1 FedEx ATP Head2Head record into a third-round clash with No. 2 seed and 2015 champion Kei Nishikori. The Japanese star narrowly held off Donald Young 6-3, 4-6, 7-6(5).

Lacko’s best chance of snapping del Potro’s winning run came as he broke serve twice to level at 4-4 in the opening set. After he lost a tight opener in 53 minutes, however, the No. 119 in the Emirates ATP Rankings scantly troubled the former World No. 4 again. Del Potro powered through the last five games of the match.

His only loss in Washington, D.C. came as an 18-year-old to Wayne Odesnik in 2007. But this was his first match at the Citi Open since the most recent of this three title runs in 2013.

Nishikori later booked his seventh showdown with the Argentine in a gripping two-hour, 28-minute affair. Young saved match points when he served to stay in the second-round clash – twice at 4-5 in the third set, and once more at 5-6 – before he fought off a further two match points in the deciding-set tie-break.

American Tennys Sandgren landed his maiden ATP World Tour match win with a 7-6(2), 6-3 victory over Japan’s Go Soeda. Sandgren thumped down 10 aces and conceded just two points on his first serve in the opening-round clash. He never faced a break point.

“It feels good. It’s still kind of different being in the main draw on my own ranking,” Sandgren said. “Obviously they’ve got the extended draw here so I feel like I had a small opportunity here to try and win a match or two. I think I played well tonight. Feel like I found some good form so I’m excited about that.”

Australian No. 10 seed Nick Kyrgios is his next opponent. The pair has never faced off.

“That’d be the best player I’ve ever played against, it’s exciting,” Sandgren said. “I hope I bring a good level. I hope the tennis is fun.”

In his first outing as top seed at an ATP World Tour 500 event, Dominic Thiem is comfortably through to the third round of the Citi Open on a soaked Tuesday. A rain-delayed start in the US capital failed to dampen the Austrian’s debut as he powered past Henri Laaksonen 6-3, 6-3.

The 23 year old dropped just one point on his first serve and never faced a break point against the Swiss. It marked his first match since he fell to Tomas Berdych in five sets in the fourth round at Wimbledon.

No. 8 seed Jack Sock advanced to the last 16 for the third straight year after he eked out a narrow 7-6(2), 7-6(6) victory over Romanian Marius Copil. Neither player faced a break point throughout, but it was Sock who proved steadier in the tie-breaks.

The American sealed the win on his second match point when Copil rolled a backhand wide. He will look to make it three straight quarter-finals in Washington when he next meets countryman Jared Donaldson or Australian Marc Polmans.

“He’s a very tricky player. He’s a tough opponent for sure, especially on a court like this,” Sock said.

“It’s a little bit quicker than last week, and he serves cannons. He’s got a great first serve, great second serve … He’s not an easy break at all. I’m definitely happy to get through in straights.”

Russian former World No. 20 Dmitry Tursunov used a protected ranking to make the main draw after ongoing injuries. The 34 year old ground out a 6-4, 6-7(4), 6-4 result over American Mitchell Krueger to set a second-round meeting with No. 11 seed Gilles Muller.

Kyle Edmund was too solid for #NextGenATP player Hyeon Chung, of Korea. The Brit sent down seven aces as he raced through 6-3, 6-1 to set a second-round clash with No. 4 seed Grigor Dimitrov.

Marcos Baghdatis, a former world No. 8 in the Emirates ATP Rankings, also advanced past the first round after he saw off Israeli qualifier Edan Leshem. Neither player managed to break in the opening set before the Cypriot ran away with a  7-6(1), 6-0 result. Ryan Harrison is next.

First coach and most important lesson he taught me
My first coach was my dad, and I think the lesson he definitely instilled in me was hard work. We worked very hard and he said in order to chase your dreams, you definitely have to put in the effort and that’s something that’s really stuck with me throughout my career.

First pinch-me moment on the ATP World Tour
Playing a practice set with Federer in Miami. I had been on the tour for a little bit, and I had seen some of the top guys… I remember I won the practice set, too. I know in hindsight it’s just practice stuff but that was a pretty surreal feeling… That was the year I beat Novak as well (2008). I would have said that but practising with Federer was just a couple days earlier. 

First thing I bought with prize money
I bought my current wife, girlfriend at the time, Kelsey, a trip to Australia (Australian Open, 2009). So that was cool. That was also after my first year so definitely some of my prize money went to that.

First celebrity crush
It’s cliché but just like me and probably everybody else at the time, it was [Anna] Kournikova.

First album I bought?
I think it was the Offspring, “Americana”. That was the “Pretty Fly For a White Guy” CD… Off the album, I think “Staring at the Sun” was my favourite.

First pet
The first pet I had was a little Maltese poodle, her name was Lulu. We got her when I was six. We always laughed because she cost like 60 rand, which is like $8. But I think she passed on some sort of bacterial something to me, because I ended up having my appendix taken out because of her. I don’t want to blame her for it without concrete proof but we ended up laughing about it. The doctor said there was a good chance it might have been from the puppy, so she ended up costing us a little bit more [than $8] but she was great. She was my childhood dog so obviously we had a lot of memories with her.

More ATP Firsts: Bryan Brothers

At the end of another hot and humid day in Washington, DC, Gael Monfils surely wanted nothing more than to head to his hotel room and relax in air conditioning.

But every time he turned to hop into his tournament-provided vehicle on Monday evening, he kept being stopped.

“Monfils, Monfils!” fans shouted.

So the popular and affable Frenchman halted, gazed at who had said his name and kindly followed their instructions, smiling for back-to-back selfies with grinning fans.

Monfils could easily have begged off, politely declining the requests and waving goodbye. Surely the fans would have understood. The guy wants to go home after a day of work, who could blame him?

But, just as he goes above and beyond with his kindness on the court by saying “Thank you” to ball kids, Monfils extends his generosity to fans as well.

“I think it’s the way I am. It’s the way I’ve been raised,” Monfils said on Tuesday at the Citi Open. “I think someone gives you something, you have to say ‘Thanks’. I think fans are very important to us… I think I can take a few minutes. It’s the minimum that we can do.”

His kindness is noticed. Long-time tennis fan Mark Hicks became one of the countless number of Monfils fans who have posed for a selfie with the six-time ATP World Tour titlist. Hicks snagged Monfils while the Frenchman was rushing between interviews and tournament obligations.

“I sort of was surprised,” Hicks said about Monfils’ response, which was to pose and smile even though he was busy. “I think he’s a nice guy and that’s part of it.”

Hicks, who teaches tennis for the Citi Open beneficiary, the Washington Tennis & Education Foundation, said he’s glad Monfils and other ATP World Tour players take a few minutes to appreciate fans.

“Give a picture. Give a handshake. That’s all we want. We aren’t trying to corral them or anything like that,” said Hicks, who ranks Monfils as his second-favourite player, behind you know who.

“Everybody loves Roger,” Hicks said in between laughs.

Monfils, however, isn’t some lovable loser. The 30 year old arrives in Washington to defend his Citi Open title from a year ago, his maiden and lone ATP World Tour 500 crown.

“It’s a great feeling. It’s always very good to come back to the place where you played good the year before,” Monfils said. “This tournament suits my game.”

Last year, Monfils saved a match point to beat Croatian Ivo Karlovic for the title, a match that Hicks and thousands of others saw. It was part of a season-long highlight reel for Monfils and his fans.

The 6’4” right-hander qualified for the Nitto ATP Finals in London for the first time and ended the season at No. 7 in the Emirates ATP Rankings, a career-high year-end Emirates ATP Ranking.

This season, injuries have hampered Monfils. He pulled out of Miami, Monte-Carlo and Rome because of injuries to his left knee and Achilles tendon. He arrives in the U.S. capital with a 16-11 record.

But Monfils could be turning his season around just in time for his throngs of fans in Washington. He reached his first final of the year last month, falling to Novak Djokovic in the Aegon International title match in Eastbourne.

Win or lose, you can bet on Monfils making time for ball kids and his fans, as he’s done throughout his career.

There were plenty of keenly contested first-round encounters on Tuesday at the Generali Open, in the medieval ski resort town of Kitzbühel.

Colombian qualifier Santiago Giraldo extended his perfect record to 4-0 against 2011 and 2012 titlist Robin Haase mid-afternoon in a 7-6(6), 4-6, 6-4 win over two hours and 13 minutes. Fifth seed Haase hit 19 aces, but, having managed to save two set points at 5-6 in the first set, could not convert his lone opportunity at 6/5 in the tie-break. Giraldo now challenges Austrian wild card and last year’s semi-finalist Gerald Melzer or Carlos Berlocq of Argentina.

German and Kitzbühel resident Philipp Kohlschreiber, who captured the 2015 title (d. Mathieu) having reached the 2012 final (l. to Haase), didn’t have things all his own way in a 7-5, 3-6, 6-3 win over Argentinean qualifier Facundo Bagnis over two hours and 11 minutes. Kohlschreiber led by a set and 2-0 in their first meeting since the 2014 US Open. He now goes onto face seventh-seeded Czech Jiri Vesely, who was a 6-4, 6-4 victory over Yannick Hanfmann, last week’s J. Safra Sarasin Swiss Open Gstaad (l. to Fognini).

Bagnis’ compatriot, eighth seed Horacio Zeballos, saved four match points and broke Rogerio Dutra Silva’s serve just once (nine of 10 break points saved) in a two-hour and 54-minute victory, 2-6, 7-6(11), 7-6(4). Zeballos first held a set point on Dutra’s Silva’s serve at 5-6, 30/40 in the second set, before converting his fourth chance in the tie-break. Dutra Silva, who would recover from a 2-4 deficit in the deciding set, squandered match point opportunities at 6/5, 8/7, 10/9 and 11/10 in the second set tie-break. Zeballos will now face fellow Argentinean Renzo Olivo or Brazilian lucky loser Thiago Monteiro in round two.

 Watch Live On TennisTV

 Watch Full Match Replays