"I don't know if someone in the next 10 years will be able to win five or six Wimbledons," the retired tennis great said during a conference call Monday leading to next month's induction into the Rogers Cup Hall of Fame in Toronto.
Sampras, who will also play in the Rogers Legends Cup, and Federer have both won seven singles titles at the All England Club. Scotland's Andy Murray won his first Wimbledon crown this month.
"This was Andy's time. It was Andy's event to go and get and he did it," Sampras said. "He's definitely the man to beat at the U.S. Open."
Murray is ranked No. 2 behind Novak Djokovic. David Ferrer is No. 3, followed by Rafael Nadal and Federer.
"I think the biggest thing for me is Murray in the past 12 months has just stepped up," Sampras said.
But he doesn't see anyone being able to conquer Wimbledon's grass courts the way he and Federer did.
"Roger and myself, our game on grass was so ... dominant," Sampras said. "I think Murray can win some more and Djokovic, but I don't think that dominant game is out there that's going to win it seven times. But I could be wrong."
Of course, there is always the possibility Federer could add another. After his second-round loss at Wimbledon this year, he switched to a larger-faced racket.
"I don't know where his head's at, whether he's going to stick with it," said Sampras, who switched to a similar racket after he retired.
Sampras says it helped his backhand and made his serve more powerful.
"I wish I would have tried it, at least a little bit on the clay, when I was playing," he said. "It would have helped me a little bit."