Carlos Alcaraz and Brandon Nakashima have surged into the ATP Tour spotlight in Rio de Janeiro and Delray Beach.

Alcaraz & Nakashima Were Ready For This Moment

This week's breakout teens Carlos Alcaraz and Brandon Nakashima cut their teeth on the ATP Challenger Tour in recent months

It was one of the more raucous, riveting scenes of 2019. Thousands of fans were screaming in full throat as a 16-year-old Carlos Alcaraz stood on Center Court at the Copa Sevilla. The line extended for blocks outside the tournament site as they hoped to catch a glimpse of their much-hyped native son.

With the sangria flowing, they danced, sang and screamed even louder. In other words, it was your typical Thursday evening on the ATP Challenger Tour in Spain.

Ranked outside the Top 500 at the time, Alcaraz soaked up the energy and emotion from his countrymen, vaulting to a surprise quarter-final appearance. It was on that day in September that Alcaraz became the youngest player to reach the last eight of a Challenger since Felix Auger-Aliassime in 2015. Having primarily focused on junior tournaments last year, the Spaniard took the next step at the Challenger level on only six occasions. But he would make the most of those opportunities.

At that age, signature victories over in-form players like Jannik Sinner, Christopher O'Connell and Pedro Martinez, can inject a surge of confidence and momentum for the coming weeks and months. And for Alcaraz, the ability to compete in front of legions of Spaniards proved to be equally as critical in his early development.

For someone as young as Alcaraz, playing in such an electric atmosphere akin to a Grand Slam or ATP Masters 1000 event, can serve as essential preparation for life at the next level. Flash forward to this week and Alcaraz was meeting World No. 41 Albert Ramos-Vinolas at the Rio Open presented by Claro. What did the 16-year-old identify as a source of confidence in his ATP Tour debut? His time on the ATP Challenger Tour.

"Those experiences helped me a lot, to become more comfortable in big matches like these," said Alcaraz. "They helped me to manage the nerves. I remember that in those tournaments I was very nervous. There were some matches that made me doubt how I was performing, but those moments made me learn to just enjoy the moment. That removed the nerves."

Alcaraz says the biggest lesson learned on the Challenger circuit has been managing his nerves in the big moments. That was on full display on Tuesday, as he edged Ramos-Vinolas 7-6(2), 4-6, 7-6(2), capturing his ATP Tour debut after nearly four hours on court. It was a rollercoaster affair that saw the Juan Carlos Ferrero pupil battle back from 0-3 down in the deciding set. For a 16-year-old to remain composed and relaxed in such a moment is a testament to the work he has put in at the lower level.

"Those matches taught me how to let things go on the court and stay in the moment. The small things like breathing and relaxing in the right moments are important. Just managing the moments in the right way."

Up to a projected career-high in the Top 350 of the FedEx ATP Rankings, Alcaraz will look to continue finding that spark at the Challenger level over the coming months. There are consecutive tournaments on home soil in Madrid, Marbella, Murcia and Villena in March and April.

For Nakashima, it has been a rather similar experience. The 18-year-old took a different path than his Spanish counterpart, initially opting for the college route. The American turned pro after a successful freshman season at the University of Virginia and, like Alcaraz, enjoyed immediate success on the ATP Challenger Tour in 2019.

Poised for a breakout 2020 campaign, Nakashima has already thrust himself into the spotlight. Making his ATP Tour debut, he is into the quarter-finals at the Delray Beach Open by VITACOST.com. Guaranteed to rise inside the Top 260 of the FedEx ATP Rankings, the unseeded wild card has defeated Jiri Vesely and Cameron Norrie without dropping a set.

If you've been following Nakashima in recent months, this should be of little surprise. If you haven't, here's all you need to know about the American teen with the steely resolve and relentless drive...

Flashback just two weeks ago, when Nakashima was making a charge at the RBC Tennis Championships of Dallas. If there was ever a turning point for a young player in search of confidence and belief, look no further than this.

Competing in just the ninth Challenger event of his young career and facing his biggest foe yet, top seed Frances Tiafoe, it proved to be a seminal moment for the American on a Thursday night. Crowds in Dallas are notoriously packed throughout the week, and with NBA legend Dirk Nowitzki in the house, Nakashima and Tiafoe put on a show under the lights at T Bar M Racquet Club.

An air of tension filled Stadium court, as the Americans traded blows for two hours and 18 minutes. Neither was willing to concede an inch, as Tiafoe battled from a set and a break down to prevail 3-6, 7-6(2), 7-5. It was counterpunch after counterpunch, with a bevy of baseline bombs exchanged throughout the encounter and Nakashima's steely resolve on full display.

The 18-year-old admitted he was quite disappointed after the match, but he understands that gritty encounters like these can only help him as he looks to progress beyond the Challenger level.

"What I'm doing doesn't really surprise me, to be honest," said Nakashima. "I know I have a good game and can compete with all these guys. Even before I went to college, I had that mindset. It's just all about having these experiences, getting more mature and physically bigger and stronger."

Nakashima did not back down from the Tiafoe test, even as his opponent repeatedly fought back in the second set and deep in the third. Where many 18-year-olds would acquiesce at the first sign of resistance, Nakashima is wired differently. You can call him a machine or just a teenager with an incredibly dialed-in temperament, but regardless, that attitude is paying dividends as he begins to battle the established pros.

"All my coaches have always told me that I'm playing my best when I'm aggressive. I just try to be myself on the court. I'm always going to attack on both my forehand and backhand, come to the net as much as possible and use a lot of variety in my game. That is who I am."

With former Wimbledon champion Pat Cash joining his coaching team this week in Delray Beach, Nakashima will look to go one step further when he faces Yoshihito Nishioka in Friday's quarter-finals.