Roger Federer said that he was happy to get past the big-serving John Isner in straight sets to reach the US Open quarter-finals.
The second-seeded Swiss beat the American 7-6 (0), 7-6 (6), 7-5 in two hours and 40 minutes.
In a chat with reporters afterwards, Federer said that he knew that it would be a tough match-up especially trying to break the Isner serve.
"I knew of the toughness of the match-up. We weren't really getting many chances. It was going to be very tough for both of us to break.
"In the tie-break you have to take the right decisions and that first set was key in a battle of serves. The second tie-break was crucial," said Federer.
"I wasn't feeling as good as I was in the first. John was going for big shots, and I wasn't as confident. I was glad to make it."
"It was very good to break and win in that last game of the match."
"It's unbelievable how John was able to play those second serve so fast. The average was like 115 mph, impressive to say the least," he added..
In last year's US Open semi-final, Federer unexpectedly lost to Marin Cilic, who went on to win the title. The Swiss said that he was much better prepared physically this time around.
"The Monfils match last year took some emotional energy out of me. I didn't feel bad going into Cilic's match. I played and felt tired somehow last year.
"I told myself it couldn't happen again this year. I had a great preparation playing in Cincinnati. Clearly, I feel very good about my chances in the quarters now.
"I am coming in with a good mind set and a good body."
In the quarter-finals, Federer will face Frenchman Richard Gasquet, who beat Tomas Berdych 2-6, 6-3, 6-4, 6-1.
"I'd rather play against Gasquet, he is a great player and I am sure I am going to face the toughest Gasquet I have ever met," said Federer.
"He is going to play at the back, construct the points and hit hard on his backhand. But I feel like I can still have that match in my racquet."