Stefanos Tsitsipas celebrates birthday win over Khachanov in Toronto

WATCH: Tsitsipas catches up with the Tennis Channel Live Desk after his straight-sets win over Karen Khachanov.

“Change of thrones.” Stefanos Tsitsipas may have coined a phrase when he said those words after his first-round match in Toronto earlier this week.

Tsitsipas was talking, naturally, about Topic A in men’s tennis these days: Are we finally, after nearly 20 years, in the waning days of the Big 3’s reign? Is anyone from the tour’s younger set ready to grab the baton from them and run to No. 1 with it?

The opportunity is certainly there right now. For the first time since 2001, Roger Federer, Novak Djokovic, and Rafael Nadal won’t participate in either of the summer hard-court Masters 1000s in Canada and Cincinnati. Federer, who has knee issues, and Nadal, who has foot issues, may not make it to the US Open.

“I think there’s room for new stars,” Tsitsipas said. “It’s been a lot about them in recent years, and I think now it’s showing that things are changing. Things are kind of—we see kind of different generation of players stepping up and showing what they are capable of.”

I think there’s room for new stars. It’s been a lot about them in recent years, and I think now it’s showing that things are changing. Things are kind of—we see kind of different generation of players stepping up and showing what they are capable of. Stefanos Tsitsipas

He’s not wrong in that assessment. This year, among Tsitsipas’s age cohort, Daniil Medvedev has reached No. 2 in the world; Matteo Berrettini has reached his first major final, at Wimbledon; and Alexander Zverev has won an Olympic gold medal. Tsitsipas himself was one set away from toppling Djokovic in the Roland Garros final, and has now moved up to No. 3 in the rankings.

“We, ourselves, we have generated our own team of people and fans that support us, give us love, and are there for us in each single match following us,” Tsitsipas said of the ATP’s younger contenders. “We want to do as good as they have done so far.”

Tsitsipas celebrated his own birthday on Thursday—his 23rd—in style, with a 6-3, 6-2 win over Karen Khachanov.

The 25-year-old Russian is another highly-touted member of Tsitsipas’s generation who has shown signs of progress this summer. He made the quarterfinals at Wimbledon, and won a silver medal in Tokyo. Right from the start, though, it was clear that today was not Khachanov’s day. In the third game, he double-faulted, made two easy forehand errors, and was broken. Tsitsipas held out to win the first set, broke Khachanov to start the second, and broke him again for good measure. Khachanov had one opportunity: With Tsitsipas serving for the first set at 5-3, Khachanov earned a break point. But Tsitsipas immediately erased it with a crosscourt forehand winner, and a fist-pump.

Tsitsipas did what he needed to do to beat a struggling opponent today. Can he go further, and take the opportunity to begin that “change of thrones” he talked about? He had a breakthrough clay season, which included a win over Nadal, and which nearly ended in Grand Slam glory in Paris. But Tsitsipas has looked a little lost since. He went out in the first round at Wimbledon, the quarters in Hamburg, and in the third round, to Ugo Humbert, at the Olympics. Now he says that a few days at home in Greece have left him feeling “rejuvenated.”

“Today was a good day,” Tsitsipas told Tennis Channel’s Prakash Amritraj. “Only positives to take from today.”

There’s always tomorrow in tennis, of course, and Tsitsipas will likely face a tougher challenge from another fast-rising Next Genner, Casper Ruud. The 22-year-old Norwegian is 37-9 on the season, has won four titles, and is up to No. 12 in the rankings. A change of thrones is coming some day; Tsitsipas-Ruud may tell us something about who is going to sit in it.