The unexpected U.S. Open final between Kei Nishikori and Marin Cilic is another indication that the dominance of the Big Four is waning, says Cilic.
The Croatian pointed to Stanislas Wawrinka's Australian Open victory as the first big change, which will now be followed by a first-time Grand Slam champion at the U.S. Open. Both Cilic and Nishikori will be playing their first major final.
"Well, it's a bit of a change-up year considering all the past years that these top four guys were making to the final," said Cilic. "Wawrinka opened the doors for us from the 'second' line, and I think most of the guys have now bigger belief that they can do it on the Grand Slams."
This year, Ernests Gulbis, Milos Raonic, and Grigor Dimitrov have also reached the semifinals of a Grand Slam for the first time.
More players are now challenging the top players at big events, Cilic noted. "Just over here as well, Kei beat Wawrinka, beat Novak, and Milos, so played amazing, amazing tournament. I think it's gonna be extremely interesting for the next several, for sure, Grand Slams," he said.
Between them, Roger Federer, Rafael Nadal, Novak Djokovic, and Andy Murray had won all but one of the previous 35 Grand Slams until this season.
Cilic sees the recent breakthroughs as motivating even more players.
"They are going to get only better," he said, though he does not expect the Big Four to go away. "So the competition is going to get very difficult. But still, I mean, I feel that it's more opportunities for everybody—I mean, all these top guys for sure, and the guys from second line.''