When Mackenzie McDonald was 12 years old, he competed in Delray Beach at a junior clay-court tournament. Little did he know that just more than a decade later, he’d be playing on Stadium Court in the Delray Beach Open.

“I didn’t know about the pro tournament at the time, but I definitely had pro aspirations when I was super young,” McDonald. “I’m living out my dream now, so it’s pretty cool.”

Much of the attention on the young Americans has gone to three 21-year-olds: defending champion Frances Tiafoe, 2018 Next Gen ATP Finals qualifier Taylor Fritz and last week’s New York Open titlist Reilly Opelka. McDonald followed a different path than his compatriots, attending UCLA for three years and winning the 2016 NCAA Singles Tournament before turning professional. On Tuesday afternoon, McDonald defeated Fritz, his good friend, to reach the second round in Florida.

“They’re ranked higher than me and they’ve had some great results. I’ve had my fair share, too. But Taylor’s played this tournament four times. This is my first time, so I have some catching up to do,” McDonald said. “I’ll make my mark. I still consider myself pretty young. I know I’m not the youngest, but wins like that help prove that I’m at their level, maybe better and I just have to keep doing my job.”

McDonald first broke out on the international scene at last year’s Australian Open. After qualifying in Melbourne and beating Swede Elias Ymer in the first round of the main draw, McDonald pushed 2017 Nitto ATP Finals champion Grigor Dimitrov to the limit. The American extended Dimitrov to a fifth set, with the Bulgarian ultimately winning 4-6, 6-2, 6-4, 0-6, 8-6.

“I was happy I got a couple matches before playing on that big stage in my first Grand Slam draw off of qualifying, not a wild card,” McDonald said. “That match was massive for me, showed me what I could do, showed me my top level in a way.”

The California native maintained his momentum, reaching the fourth round of Wimbledon. Later in the season, he qualified for the Rolex Shanghai Masters, an ATP Masters 1000 event, and beat former World No. 3 Milos Raonic. McDonald may not be as young as some of his fellow Americans, but he’s improving his level just the same.

“It’s really only his third year on the ATP Tour after winning NCAAs. He started off playing the Futures circuit and had the success there and went to Challengers, had success there and really broke through last year at Wimbledon, and that’s when people really started talking about him,” said one of McDonald’s coaches, Michael Russell. “He’s had some great wins and he’s a player to contend with and we’ve been working really hard to make him believe that and [give him] the mindset that he could be a Top 50 player.

“That’s a lot of it with most of these players. All of these guys are so talented and such great athletes, but it’s having that belief and the confidence when you go out there that you are the best player on the court. Having the player buy into that and really believing that is super important.”

McDonald brings an interesting game to the court. While he stands just 5’10”, McDonald is plenty aggressive.

“I play flat and fast. I like to come in and volley, I have good returns and I’m really quick,” McDonald said. “I think some of those long points [I play] are fun to watch.”

“He’s a great ball-striker, an excellent returner, very quick and he uses his speed to take time away from his opponents,” Russell said. “He continues to look for opportunities to come to net and force the issue.”

McDonald has shown his potential, but he has only advanced to one ATP Tour quarter-final, in ‘s-Hertogenbosch last June. The World No. 84 is determined to keep working hard daily to improve his game, and with it, his results.

“Tennis is such a weird sport. You’ve just got to keep fighting every day. That’s the thing. When I first started, it was really tough at first but I was not going to give up, I just kept fighting and trying to find a way, because that’s all I could do,” McDonald said. “I really want to be good at this sport… when you keep working hard, good things happen.

“Now I’m in the Top 100, so it’s just chasing those little goals and gains and trying to make the most out of it.”

#NextGenATP Canadian Felix Auger-Aliassime had nothing to lose on Tuesday evening against second seed Fabio Fognini, and he played like it. The 18-year-old wild card picked up one of the biggest wins of his career, dismissing the Italian 6-2, 6-3 at the Rio Open presented by Claro.

“It’s at the top, for sure, with my most memorable wins,” Auger-Aliassime said. “You come here, you play the second seed, obviously you’re not favoured. But you just believe in your tennis, you believe in your game. These wins, that’s what you work for.”

Serving for the match, at 5-3, 40/15, Auger-Aliassime needed three match points, but the teenager ultimately put away Fognini, who fell to 3-5 this year, including 0-3 on clay.

“After losing the first point, I got a bit worried. You always want to win the first point of the last game, but then I recovered well with some good serves, and I think I did what I had to do on the match points,” Auger-Aliassime said.

The win against Fognini, who finished 2018 at a career-high No. 13 but has since fallen to No. 16, is Auger-Aliassime’s biggest win by ATP Ranking. In August, at the Rogers Cup in Montreal, he beat then-No. 18 Lucas Pouille for his first Top 20 win.

Flashback: Felix, 17, Notches ‘Statement’ Top 20 Win In Toronto

The teenager will next meet Chile’s Christian Garin, who beat Auger-Aliassime in three sets last week at the Argentina Open in Buenos Aires. Garin advanced on Tuesday in Rio with a 7-5, 6-3 win against Germany’s Maximilian Marterer.

All sixteen first-round matches took place on Tuesday in Rio, after rain washed out Monday’s schedule. Other winners include Spain’s Jaume Munar, who knocked out Argentine Leonardo Mayer 7-6(5), 6-4. The 21-year-old Munar will meet Brit Cameron Norrie, who needed only 59 minutes to beat sixth seed Dusan Lajovic 6-2, 6-1.

Nick Kyrgios held his nerve to win an all-Aussie battle against fifth seed John Millman on Monday at the Delray Beach Open by VITACOST.com, firing 19 aces to advance 6-4, 6-7(1), 7-6(3).

“My serve keeps me bailing me out of these types of matches, which is pretty fortunate for me,” said Kyrgios. “I knew it wasn’t going to be easy. John is one of the toughest competitors on tour and he’s a good mate of mine, so I’m just happy to get through with the win.”

Having lost their only previous FedEx ATP Head2Head meeting in the first round of the 2017 US Open, Kyrgios proved eager to turn the tables. He opened the match with a break of serve and rode that slight advantage to take the first set. Both men held serve throughout the second set to force a tie-break, but Kyrgios double faulted to give Millman a 3/0 lead and the fifth seed forced a decider.

The final set featured 12 more routine service holds to bring another tie-break, but Kyrgios raised his level to control the baseline rallies and advance after two hours and four minutes. He’ll take on either 2015 champion Ivo Karlovic of Croatia or Radu Albot of Moldova in the next round.

The opening match of the evening session saw wild card Lloyd Harris of South Africa earn the second ATP Tour main draw win of his career with a 7-6(1), 6-3 victory over qualifier Darian King of Barbados. Harris, who made his debut in the Top 100 of the ATP Rankings earlier this month, saved three set points on his serve at 4-5 in the opening set.

“I’m happy to get the win and thought I played pretty good tonight,” said Harris. “I’ve been playing my best tennis over the past six months and if I play well, I believe I can beat anyone.”

A single break in each set was all Lukas Lacko of Slovakia required to beat qualifier Yosuke Watanuki of Japan 6-4, 6-4. Next up for Lacko is the winner between second seed John Isner of the United States and Peter Polansky of Canada.

Denis Istomin of Uzbekistan defeated Feliciano Lopez 7-6(5), 6-2 for his first win over the Spaniard in their four FedEx ATP Head2Head meetings. Awaiting him in the next round will be the winner between eighth seed Adrian Mannarino of France and Brayden Schnur of Canada, last week’s runner-up at the New York Open (l. to Opelka).

Entering the 2018 Delray Beach Open, Frances Tiafoe was No. 91 in the ATP Rankings. The American had made just one tour-level quarter-final, which came the previous week at the inaugural New York Open.

“I had no expectations at all,” Tiafoe said.

In the first round, Tiafoe faced Matthew Ebden, who defeated the American with the loss of just five games the month before. But the American hung tough after losing the second set against the Aussie to reach the second round in Delray Beach.

Next up was a daunting task: Tiafoe’s childhood idol and 2011 champion Juan Martin del Potro. The Argentine had won both of their previous FedEx ATP Head2Head meetings, including a straight-sets victory at the Australian Open just weeks before.

But Tiafoe summoned some of his best tennis, converting on his fourth match point to defeat Del Potro after two hours and 27 minutes in a three-set thriller. It was just his second victory against a Top 10 opponent.

“I was cool with the tournament after I beat Delpo, honestly. Could have lost in the next round and I really wouldn’t have cared,” Tiafoe said.

Perhaps more impressively, Tiafoe earned the respect of his idol, Del Potro. The ‘Tower of Tandil’ would go on to claim his first ATP Masters 1000 title at the BNP Paribas Open and climb to a career-best World No. 3 in August, so it took a lot for Tiafoe to beat him.

“Frances has everything to be in the top positions very soon. He has talent, the power to play long matches. [He has] the smart things to be playing in front of the top guys, also. I like to see him enjoying this sport,” Del Potro said on Monday. “I know he has a little bit of pressure on his back because the whole country is expecting too much of him. But he’s going to be a better player in a very short period because he’s already a good player for us and I would love to watch him playing finals and winning tournaments.”

“That was great,” Tiafoe said upon hearing of Del Potro’s encouraging words. “It’s still funny hitting with him and spending time with him. It’s good to see him back. He’s such a nice guy and anything he says, even saying hi to me, means a lot to me. I’m a huge fan.”

The tough part for Tiafoe was that, at that point, he was only in the quarter-finals. In the next two rounds, Tiafoe had to play then-reigning Next Gen ATP Finals champion Hyeon Chung and #NextGenATP Canadian Denis Shapovalov, both of whom were inside the World’s Top 50. What made it tougher was that due to rain on Friday evening, Tiafoe had to complete his quarter-final triumph against Chung on Saturday before returning later in the day to face Shapovalov.

“We were just taking it one step at a time and doing the best we could every day,” said Tiafoe’s coach, Zack Evenden. “We did a great job of that and it was a fairytale week.”

Tiafoe went on to beat German Peter Gojowczyk to lift his maiden ATP Tour title, becoming the youngest American to claim a tour-level trophy since a 19-year-old Andy Roddick at 2002 Houston. Tiafoe struck an ace down the T on championship point, then fell to his back in celebration.

“Complete relief, joy. That feeling, we’ve spoken about that a lot and that feeling, it’s going to be tough to replicate that. We didn’t expect it,” Evenden said. “We knew he was capable of big things, but him turning around the year that quick and in that fashion, beating the players he did that week, it was definitely overwhelming.”

“To win the event was pretty cool,” Tiafoe said. “I’m happy to have my first title here in South Florida where I spend so much time. Hopefully I can do it again.”

While Tiafoe was just inside the Top 100 when he arrived at Delray Beach last year, his return this season is a different story. Not only did he qualify for the 2018 Next Gen ATP Finals in Milan, but he is at a career-high No. 29 in the ATP Rankings, fresh off his first Grand Slam quarter-final at the Australian Open. Tiafoe opens his title defence against Daniel Evans.

“I don’t feel any pressure this year, either. It’s kind of just another event I want to do well in. That’s where my head is right now. Obviously I gave myself a pretty good start [to the year], so there’s no real pressure,” Tiafoe said. “I’m just trying to get some momentum going for these next couple of weeks.”

Monday’s matches were a wash at the Rio Open presented by Claro, with all seven scheduled singles matches canceled due to rain in Rio de Janeiro.

Only two matches made it on court. Federico Delbonis of Argentina leads seventh seed Malek Jaziri of Tunisia 5-3 and Roberto Carballes Baena of Spain leads eighth seed Nicolas Jarry of Chile 4-3.

The top four seeds headline Tuesday’s schedule of play that features all 16 first-round matches. Top seed Dominic Thiem of Austria takes on Laslo Djere of Serbia in the evening session, followed by fourth seed and defending champion Diego Schwartzman of Argentina squaring off against 2016 champion Pablo Cuevas of Uruguay.