Rafael Nadal warns fans that 'Big Three' era, alongside Novak Djokovic and Roger Federer, is coming to an end

Ahead of his US Open final against Daniil Medvedev, Spaniard says trio's grand slam domination is reaching a finale

Rafael Nadal, 33, celebrates his victory over Matteo Berrettini in the US Open semi-final at Flushing Meadow on Friday. AFP

Rafael Nadal warns men's tennis fans that the "Big Three" era is coming to an end very soon, and he's not all that worried about it.

The 33-year-old Spaniard, an 18-time major champion, will try to add to his trophy haul on Sunday when he faces Russia's Daniil Medvedev in the US Open final.

Together with 20-time Grand Slam winner Roger Federer and 16-time Slam champion Novak Djokovic of Serbia, Nadal has been part of a historic trio whose members own 54 of the past 65 Grand Slam men's singles titles – including the past 11 in a row.

Toss in Britain's Andy Murray, a three-time Grand Slam winner who is making a singles comeback after hip surgery, and you have a fourth star of the times.

But, Nadal warns, it's getting time to close that chapter.

"We don't need to hold this era anymore," Nadal said. "We have been here for 15 years almost. Hopefully, but for my personal interest. At some point, these days, going to happen sooner than later that this era going to end.

"Is arriving to the end. I am 33. Novak is 32. Roger is 38. Andy is 32, too. The clock is not stopping. That's part of the cycle of life.

"I'm not much worried about this because in tennis always going to be great champions."

There are rising stars. Fourth-ranked Austrian Dominic Thiem, 25, lost the past two French Open finals. Number five Medvedev, 23, is in his first Slam final. Germany's sixth-ranked Alexander Zverev, 22, and Greece's eight-ranked Stefanos Tsitsipas, 21, are charging toward the top as well.

But the "Big Three" have dominated like no other generation in tennis, whether the 1960s era of Roy Emerson setting the record of 12 career Slam titles, or the American-dominated 1990s run of Andre Agassi and Pete Sampras, whose 14 Slam wins became the new standard.

Nadal owns 12 French Open titles. Federer has eight Wimbledon crowns and six from the Australian Open. Djokovic has captured seven titles in Australia and five more at Wimbledon.

Since Federer won his first Slam title to launch the Big Three era at Wimbledon in 2003, only five men's major finals have been played without either the Swiss star, Djokovic or Nadal being involved.

Djokovic, winner in four of the previous five Slams, went out in the US Open fourth round to three-time Slam winner Stan Wawrinka, a left shoulder injury forcing the Serbian star to retire.

And Federer, who lost an epic five-set Wimbledon final to Djokovic in July, was ousted in the quarter-finals by Grigor Dimitrov, who had lost their prior seven matches.

Federer was blunt when asked what it meant for tennis not having two of the Big Three in the US Open's last four. "Not much," Federer said.

Federer said he expects to have more chances at Grand Slam titles even at age 38.

"I don't have the crystal ball. Do you?" Federer said. "So we never know. I hope so, of course. I think still it's been a positive season. Disappointing now, but I'll get back up, I'll be all right."

Djokovic, the youngest of the trio, says he is planning a comeback in Tokyo and his aim remains going to the top of the career Grand Slam win list, potentially after Nadal and Federer have retired.

"I have, of course, desire and a goal to reach the most Slams and reach Roger's record," Djokovic said. "But at the same time, it's a long road ahead hopefully for me.

"I hope I can play for many more years. I'm planning to. I mean, I don't see an end behind the corner at all. Now it's a matter of keeping my body and mind in shape and trying to still peak at these kind of events."

Time is on Djokovic's side, but Nadal sees the journey as more meaningful than the destination when it comes to the all-time Grand Slam title record.

"Of course, I would love to be the one who achieve more Grand Slams, but I still sleep very well without being the one who has more Grand Slams," Nadal said.

"You cannot be all day frustrated or all day thinking about what's your neighbor have better than you. You have to be happy with yourself. You have to do your way.

"If you are the one to achieve more, fantastic. If not, at least I give my best during all my career."