Novak Djokovic has picked out Grigor Dimitrov and Milos Raonic as the rising stars to watch out for at the US Open.
Stanislas Wawrinka has already broken the so-called big four's monopoly on Grand Slam titles by winning this year's Australian Open and Djokovic is wary of more up-and-coming contenders at Flushing Meadows.
The Serbian, Rafael Nadal, Roger Federer and Andy Murray dominated 16 straight major events until Switzerland's second string gatecrashed the party in Melbourne.
Normal service was resumed when Nadal prevailed at Roland Garros once more and Djokovic obliged at Wimbledon, but with the Spaniard out through injury and the chasing pack closing the gap, there could yet be another twist in New York.
Bulgarian Dimitrov has picked up titles on three different surfaces in 2014, winning at Queen's Club on grass, in Bucharest on clay and in Acapulco on an outdoor hardcourt, as well as reaching the last eight in the Australian Open and the semi-finals at Wimbledon.
Fellow 23-year-old Raonic, born in Montenegro but a member of Canada's Ryder Cup team, has risen up to number six in the rankings after claiming outright glory in Washington and also made the last four at the All England Club.
"I have been saying before that it's positive to see that there is a new generation coming up of young players who are challenging and also winning against top players in the big events and who are contenders for big titles," said Djokovic.
"Raonic and Dimitrov are on top of that list - and they have been playing some really good tennis. They played semi-finals of Wimbledon. So I'm sure that people who care about the sport and follow this support love to see new faces.
"The dominance of the top four players has been in this sport for a long time already, the last decade or so, so we didn't have many young players who were able to challenge for top spots and win Grand Slam titles. But this is something that is happening now."