Stefanos Tsitsipas and Dominic Thiem will vie for one of the most prestigious titles in tennis at the ATP Finals on Sunday, with the suggestion the sport’s established order could finally be under threat.

For only the third time in 16 years the final of the season-ending tournament in London will not feature at least one of the ‘big three’. In fact, this is the second time in the last three editions of the event.

While Rafael Nadal, Novak Djokovic and Roger Federer continue to be the dominant forces on the Grand Slam stage, those fighting to bridge the gap are making important strides.

Federer: Next Gen have proved their point

Federer, whose hopes of a record-extending seventh title at the ATP Finals were ended by Greek Tsitsipas in the semi-finals, admitted the next generation of talent are catching up with the old guard with more consistent displays.

Thiem, far from a young player at 26, has already beaten Federer and Djokovic this week in the round-robin stage to reach the showpiece to add further credence to the belief the gap may finally be closing ahead of next season.

“Does it feel like it might be the best year yet? Possibly,” said Federer after his defeat against Tsitsipas.

“Then the only issue is that it seems like me, Novak, and Rafa are healthy, healthier than maybe in previous years, as well.

“So from that standpoint, I think they have proved their point this year by qualifying for the Finals, and also now Dominic showed again at these Finals, and winning five titles, beating all of us top guys.

“Definitely it’s that next step they need, and seems like Dominic is in his absolute prime right now. Yeah, I would think so.

“But then I look at the list of who finished world number one, who has been world number one all these years, and it’s just crazy that it’s always one of us.

“But we are not getting any younger. So their chances increase not because we are getting worse but because they are getting better, I believe.”