LONDON－Stefanos Tsitsipas said he was ready for a breakthrough Grand Slam victory after winning the ATP Finals in London－but a glance at recent history invites caution.

The 21-year-old Greek was in bullish mood after he beat Dominic Thiem, having ousted Roger Federer in the semifinals, to become the season-ending event's youngest winner since 2001.

"I believe I'm really close to being crowned a Grand Slam champion," he said, after his 6-7 (6), 6-2, 7-6 (4) triumph in London on Sunday. "I know these are strong words that I say but I do feel I belong there."

But although Tsitsipas' victory feels significant, he is the fourth first-time champion in as many years at the season finale, which has proved a poor predictor of future success.

Last year, young German Alexander Zverev pummeled Novak Djokovic in the final but he had a miserable time at this season's Slams－while the Serb, 32, picked up the Australian Open and Wimbledon titles to take his overall tally to 16.

Rafael Nadal, 33, won a 12th French Open title and added the US Open, underlining the fact that the old guard was still very much in charge.

No member of the "Big Three"－also featuring Federer－has won the season-ending ATP Finals since 2015, when Djokovic picked up his fifth title.

Djokovic was also the last ATP Finals champion to go on to win a major title.

Injury-plagued Andy Murray has won only two trophies since he secured his sole ATP Finals title in 2016, crowning his strongest season.

And the lavishly gifted but inconsistent Grigor Dimitrov has not won a tournament since his 2017 success at the season finale.

The fact remains that despite all the razzmatazz surrounding the ATP Finals, it is the Grand Slams that are the true yardstick in tennis.

Since 38-year-old Federer won his first Slam in 2003, the Big Three have collected an astonishing 55 out of the 66 majors on offer, with Murray and Stan Wawrinka also winning three apiece.

There has long been speculation over who would be able to overthrow the established order.

Players such as Milos Raonic, Dimitrov and Kei Nishikori－members of a previous supposed "next generation", consistently failed to challenge the dominant trio.

However, that is not to say that there's no hope for the younger players, who now appear to be getting closer.

Russia's 23-year-old Daniil Medvedev pushed Nadal all the way in the US Open final in September, and should have avenged the loss at the ATP Finals where he collapsed from an seemingly impregnable position against the Spaniard.

Zverev demolished Nadal to reach the semifinals in London, but was disappointing in a straight-sets defeat against Thiem.

Tsitsipas' impressive win against Federer in the semifinals also felt like a statement of intent－backing up his victory against the Swiss at the Australian Open.

The 22-year-old Zverev predicted next year will bring a new Grand Slam champion, saying the "young guys are playing incredible tennis".

But Tsitsipas warned that it was crucial to dislodge Federer, Nadal and Djokovic in the early rounds as they tend to improve as tournaments progress, adding that the five-set format also plays into their hands.

"For the young guys it's all about time," he said.

"I don't know. We will have to beat them or wait for them."

Federer said he has heard it all before, although even he senses a possible shift at the top of the men's game.

"It's the same question every year at the end of the year, and I feel like I'm answering it the same way," he said. "But does it feel like this year might be the best (closest) year yet? Possibly."

REUTERS