The magnificent seven teenagers

Russian Andrey Rublev -- the No. 1-ranked junior player in the world last year -- had just won his first ATP World Tour-level match Tuesday at Delray Beach, Florida. The excitable local newspaper reporter wanted to know whether he had ever played Stefan Kozlov, the rising phenomenon from nearby Pembroke Pines.

"Well, yes," said Rublev, not unkindly. "Many times. We play in under-12s, under-14s, under-16s. A lot of times he won, a lot of times I won."

Their most recent significant meeting was the quarterfinals of the 2014 boys' tournament at Roland Garros, won by Rublev, who went on to take the championship and become the first Russian to win that title in 48 years. Their next meeting won't be the final of the Delray Beach Open. That's because Kozlov, the No. 3 junior a year ago, lost his first-round match to Tim Smyczek.

That didn't temper the moment in the least. For two other teenagers joined Rublev in the winner's circle Tuesday in Florida: Australian Thanasi Kokkinakis and Yoshihito Nishioka of Japan. Like Rublev, Nishioka was a winner for the first time in an ATP event.

The last time at least three teenagers reached the second round of a 28- or 32-player ATP event? More than seven years ago, when Juan Martin del Potro, Evgeny Korolev, Kei Nishikori and Sam Querrey did it in Indianapolis. Del Potro was destined to become a Grand Slam champion and Nishikori was a finalist at last year's US Open.

"First match win," said Nishioka, who is 19. "So happy. Last year at this time I was playing Futures. This year I win all my qualifying matches and play first time main draw. Many first things."

But hardly the last for Generation Next.

Nick Kyrgios, the 19-year-old from Australia, has already been to two major quarterfinals (something that hasn't happened for a teen since Roger Federer), and Croatian Borna Coric, 18, made headlines last year when he took down Rafael Nadal in Basel. They're the only teens currently ranked among the ATP's top 100, but judging by the early results this week in Marseille, France, and Delray Beach, they will soon be joined by a handful of talented teenagers.

The ATP's elite are famously graying around the edges -- the average of the top-10 players is 28 -- but there are now no fewer than nine teenagers ranked among the top 200. And that doesn't include Rublev and Kozlov. Some context: That surpasses the week of Oct. 22, 2007, when Korolev, Lukas Lacko, Santiago Giraldo, Ernests Gulbis, Del Potro, Marin Cilic, Donald Young and Alexandr Dolgopolov were all ranked in the top 200.

The lone American in the group is Rhode Island's Jared Donaldson, 18, who recently won the Maui Challenger. Long Island's Noah Rubin, 18, won the Wimbledon junior tournament last year, beating Kozlov in the final.

"We have played each other in under-14s, junior Davis Cup, the junior Grand Slams, the Orange Bowl," Kokkinakis said. "You can see how everybody's tracking, pushing through at the same time.

"It will be interesting to see who can make the transition."

For those of you who haven't been following junior tennis closely, here's a look at the (magnificent) seven teenagers who played in ATP events this week:

Borna Coric, 18, Croatia, No. 85: Back in January, Coric boldly told the Times of India he was "the best of my generation," that when he was playing well his game resembled Novak Djokovic's, and when he wasn't, Andy Murray's.

Coric later clarified those comments, but there are some people who think he will prove to be right; in an eerie way, he does resemble Djokovic. Look no further than October, when he ripped off three eye-opening wins in Basel over Ernests Gulbis, Andrey Golubev and Nadal. Coric wound up with a formidable 7-6 record in 2014 against ATP opposition.

So far this year, it's been more of a struggle. Marseille is his fifth tournament of the young season and his first-round victory over Denis Istomin was only his second. Still, there's a lot to like about the recipient of the 2014 ATP Star of Tomorrow Award Presented by Emirates. He's the youngest player to break into the top 100 since Rafa in 2003.

Thanasi Kokkinakis, 18, Australia, No. 143: At 6-foot-5, 178 pounds, he has a Kyrgios-like frame and a game that will make him a dangerous professional.

The Aussie qualified his way into the main draw two weeks running, in Memphis and Delray Beach, and defeated Filip Krajinovic in the first round to raise his 2015 record to 3-3.

"I did it the hard way the last couple of weeks," Kokkinakis said. "It's good to tough out a few matches. You feel better about yourself with a few qualifying wins and have a better feel for the court when you get to the main draw."

Kokkinakis carved out opening-round wins at the Australian Open the past two years, including a five-set thriller over Gulbis last month. He says his serve and his forehand are his biggest weapons, but even they need improving.

"My immediate goal is to crack the top 100 as quick as I can," he said. "Obviously, that's not the goal for rest of year."

Stefan Kozlov, 17, United States, No. 406: At 17 months, 17 days, Kozlov is the youngest of this distinguished group.

After losing to Tim Smyczek in the first round at Delray Beach, the native of Skopje, Macedonia, is still looking for his first ATP win. He's 0-for-4, but that streak will likely end soon. Last year he reached the finals at the junior tournaments at the Australian Open and Wimbledon and in October he advanced to the final at the Sacramento Challenger.

In December, though, Kozlov finally broke through at the prestigious Orange Bowl International Championship. He had fallen in the final three previous times, but rallied to beat Stefanos Tsitsipas in three sets to capture the under-18 title.

Yoshihito Nishioka, 19, Japan, No. 154: He grew up idolizing Nadal and Fernando Verdasco, but over time the 5-7, 138-pound player came to identify more with Chilean champion Marcel Rios.

Like Rios -- and his countryman Kei Nishikori -- Nishioka can be a dazzling shot-maker. He defeated Igor Sijsling in straight sets to open his Delray Beach appearance. Nishioka has played well in ATP Challengers and qualified for the 2014 US Open where he retired in the first round against Paolo Lorenzi.

"I need to improve my service," Nishioka said. "And I think I need to get more inside the court. I can be behind and running to defend -- I can do that. But I know I must go inside and learn to be more aggressive."

Elias Ymer, 18, Sweden, No. 189: He lost to veteran Tommy Robredo in the first round at Rio de Janeiro, but there's no shame in that. Last year Grand Slam singles champions Novak Djokovic and Marin Cilic both fell to Robredo.

Ymer scored his first ATP win last year in Bastad and qualified into the main draw of the Australian Open last month, losing to Go Soeda in a five-set first-round match.

His sporting idol is Mike Tyson and he says he'd want to play football if he weren't a tennis player. Favorite shot and surface: forehand and clay. He's coached by Magnus Norman, who has helped turn Stan Wawrinka into a world-class player.

Andrey Rublev, 17, Russia, No. 370: His ATP breakthrough came against Dudi Sela -- after losing the second set 6-1.

"It's an unreal feeling," the wild card said afterward. "Second round, I will try my best and see what happens."

So far, quite a bit's been happening for Rublev. Not only did he win the French Open junior title, but he also played a dead rubber for Russia versus Portugal last fall. After the US Open, he was invited to hit with Nadal -- the player he emulated as an 8-year-old -- for a week in Mallorca.

"He had a few advices for me," Rublev said. "The big one was keep working hard. Yes, I know I need to keep working harder."

Alexander Zverev, 17, Germany, No. 138: The Hamburg native has the pedigree to succeed in the professional ranks.

His father, Alexander, was a professional player and is now his coach. At 6-6, 189 pounds, Zverev already has some startling weapons. He reached the semifinals at Hamburg in July, beating four top-100 players, including Mikhail Youzhny, before falling to David Ferrer.

Zverev, a former No. 1 junior, qualified in France but lost to Gael Monfils. It wasn't easy, though. Zverev battled the Frenchman; the second-set tiebreaker went to a 14-12 count.