Carlos Alcaraz and Jannik Sinner have created a ‘huge void’ in men’s tennis. What does the future of their rivalry hold?

By George Ramsay, CNN

(CNN) — On an unremarkable clay tennis court in the Spanish city of Alicante, watched on by only a handful of spectators, two teenagers swipe the ball to one another with surprising vigor, belying their scrawny, adolescent frames.

The ages of each player – one 17, the other just 15 – suggest that this is unlike most other matches on the ATP’s Challenger Tour, a stepping-stone circuit for those looking to join tennis’ elite.

Over the course of three back-and-forth sets, it’s the younger protagonist who emerges victorious after an hour and 50 minutes. His name is Carlos Alcaraz, and his opponent? Another future world No. 1 named Jannik Sinner.

This match took place more than six years ago, the first meeting of a rivalry which now looks destined to define the current era of men’s tennis.

“The match was a rollercoaster for us,” Alcaraz told CNN Sports last year about his memories of facing Sinner for the first time – an appropriate precursor for what was to come. This rivalry has already seen more ups and downs and twists and turns than anyone in that thinly populated crowd could have imagined at the time.

“After the match, we went to the same locker room because I wanted to get to know him,” Sinner said in the same interview last year. “He was just an amazing talent already back in the day. You could see straight away that he was a very, very special player.”

Alcaraz and Sinner, a duo now affectionately dubbed “Sincaraz” by fans, have met 14 times on the main ATP Tour since then, nearly always in high-stakes semifinals and finals.

So far, it’s Spain’s Alcaraz who leads the nascent rivalry with nine wins to Sinner’s five, but the Italian is the current world No. 1 having occupied the top spot in the rankings since June last year.

The pair have shared the last seven grand slams between them – four to Sinner and three to Alcaraz – and, barring an injury or shock defeat, seem on a collision course to face each other in the US Open final on September 7.

Alcaraz plays big-serving American Reilly Opelka in the first round on Monday, while Sinner, having recovered from the illness which forced him to retire from the Cincinnati Open final against Alcaraz, faces Czech Republic’s Vit Kopriva on Tuesday.

The dust has barely settled from the tripartite rivalry between Roger Federer, Rafael Nadal and Novak Djokovic, but now tennis fans are left with an eerie sense of history repeating itself. Here is another matchup likely to preside over the men’s game for years to come.

Already, Alcaraz and Sinner have produced several matches worthy of a movie script: a 3 a.m. finish in the US Open quarterfinals back in 2022, a three-hour, 21-minute slugfest at last year’s China Open, and, to top them all, the longest French Open final in history earlier this year, with Alcaraz somehow triumphing from two sets and then three championship points down.

But it’s not just their knack for producing such absorbing contests that makes this rivalry so fascinating. It’s also their contrasting styles of play and on-court personas.

“Certainly, the temperamental differences are quite clear to any fan or observer,” Giri Nathan, author of “Changeover,” a new book on the rivalry between Alcaraz and Sinner, tells CNN Sports.

“Carlos loves to spring for spectacle on the tennis court. He likes to find that ingenious shot that he’s never tried before, and he’s almost cheeky in the way he tries to get away with new flourishes. With Jannik, it’s a little more methodical. Personally, I find them both captivating to watch in different ways.”

Nathan started working on his book in late 2023. By then, Alcaraz had already established himself as the most exciting and explosive talent in tennis, winning major titles at the US Open and Wimbledon. Betting on Sinner’s adjacent rise at that time, however, was more of a gamble.

“With Sinner, I think it was something I saw in the quality of his ball striking,” says Nathan. “More specifically, it’s something I heard because, if you’re lucky enough to watch Jannik Sinner play up close, it sounds unlike anything I’ve ever heard on a tennis court. In the book, I compare it to a firearm or a vehicle backfiring – it’s just a spectacular sound.”

And for all their obvious differences – Alcaraz the showman, Sinner calm and understated; Alcaraz flashy and unpredictable, Sinner steady and reliable – Nathan has also been struck by just how much these two men have in common.

Both are mild-mannered, close to their families and extremely dedicated to the pursuit of tennis excellence. Both lead “quite monk-like and ascetic lives,” according to Nathan – contrary to Alcaraz’s Ibiza-going, party-animal reputation – and have “a genuine respect” for one another.

The similarities also extend to what they do on the court.

“I think what distinguished them was their excellence in ground strokes – their movement and their ability to not just be quick and get to balls, but even when they’re reaching for that far away ball, to be able to uncoil and hit that ball 100 miles per hour,” adds Nathan.

“That combination of being offensive from defensive court positions is very rare. It distinguished, I think, Federer, Nadal and Djokovic in their tennis. And I think these guys are, in a sense, taking it up a half notch in at least the power that they have.”

Comparisons with Federer, Nadal and Djokovic – the so-called “Big Three” of men’s tennis – will likely be inescapable throughout the careers of Alcaraz and Sinner, such has been the neatness with which one rivalry replaced the other.

As the game’s latest rivalry develops, tennis fans will watch with interest to see if it follows the same pattern of two becoming three, perhaps even four. Djokovic was a late arrival to the Federer-Nadal rivalry, while Andy Murray also battled his way into contention for a seat at the table, beating the “Big Three” more than any other player.

A genuine third cast member has yet to emerge in the Alcaraz-Sinner show, but there are possible contenders. João Fonseca, a 19-year-old from Brazil who won his first ATP Tour title in February, is a candidate, as are American Ben Shelton and Great Britain’s Jack Draper – both contemporaries of Alcaraz and Sinner who have enjoyed deep runs at grand slams.

“I feel like there’s this huge void now where Sinner and Alcaraz are floating kind of above the fray, but there’s huge opportunities for whichever player can emerge into that kind of upper-middle-class zone,” says Nathan, adding that it’s “entirely possible that the true contender who can hang with these two guys is maybe still 15, 14, 16 years old.”

In between an aging Djokovic and players like Daniil Medvedev and Alexander Zverev – part of the unenviable generation to follow the “Big Three” – unable to meet the extraordinary standards of Alcaraz and Sinner, tournaments sometimes feel like a two-horse race.

But an interloper to this rivalry, Nathan believes, would make the men’s game more compelling and “bring out new emotional texture” to the friendly feud shared by Alcaraz and Sinner. The pair are cordial to each other on and off the court, even sharing a private jet together after last year’s China Open final.

“I’ve been hearing from fans that they want a little more beef there, and they want a little bit more teeth bared in this rivalry because it is super congenial,” says Nathan. “There is something fun as a fan when there’s that seed of genuine hostility, and I wonder if it’ll enter this rivalry ever.”

For now, Alcaraz and Sinner seem firmly lodged at the top of men’s tennis, the former on five grand slam titles and the latter on four. Those tallies will undoubtedly grow in the years to come, while both players are still targeting a career grand slam by winning all four majors. Alcaraz needs the Australian Open and Sinner the French Open – which, of course, he was only a point away from winning earlier this year.

So who will ultimately get the upper hand in this era-defining rivalry? According to Nathan, it’s far from clear-cut, particularly with the strides that Sinner has made over the past 12-plus months – all while negotiating a three-month doping ban.

“I feel like my answer to this question changes every day, which is a testament to how good the rivalry is,” says Nathan.

“I’m going to lean Alcaraz at the moment. I think being two years Sinner’s junior is an advantage … (and) his ability to continually find new modes of play when he needs to – to really snap into focus when the scoreboard really demands that of him – is pretty remarkable to watch. I’m not sure I’ve seen anything like it.

“When it matters most,” Nathan adds, Alcaraz is “the most audacious, the most creative, the most electric tennis player you’ll see.”

To have that talent showcased against a player with whom he is so evenly matched, and on the biggest stages the sport has to offer, is a rare treat for tennis fans. Whichever direction this rivalry takes, blockbuster entertainment is guaranteed along the way.

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CNN’s Aleks Klosok contributed to reporting.