The third-seeded Djokovic beat Blake 6-1, 7-6 (4), 6-3 in a wind-whipped Arthur Ashe Stadium on Saturday night. Serbia's Djokovic made only 13 unforced errors — 18 fewer than Blake.
"It's a big mental struggle, when you have such a strong wind, to find a way how to try to play good tennis," Djokovic said, "especially if you have somebody across the net who is so aggressive, taking everything early and playing a risky game."
After having knee surgery in September 2009, Fish set about changing his diet and trimming his body, and he's lost more than 30 pounds to get down to about 170.
"He's playing maybe his best tennis at this moment," Djokovic said. "He's moving really well. He's serving as good as he served always. He has a lot of talent. He's recognizing the moment, coming to the net. He has a lot of variety in the game. I guess I have to be on the top of my game to be able to win."
Djokovic was the U.S. Open runner-up in 2007, and made it to the semifinals in 2008 and 2009 — losing to Roger Federer every time.
Blake is a two-time quarterfinalist at Flushing Meadows, but not since 2006. Once ranked in the top five, the 30-year-old Blake is now 108th after a series of injuries and poor results, and he said he plans to take the next six weeks off.
As for his longer-term future in the sport, the 30-year-old Blake said that he aims to play in the 2011 U.S. Open and hopes Saturday night's match wasn't his last in Arthur Ashe Stadium.
"If it was, you know, I competed my heart out. I did everything I could," Blake said. "But I think I got more in me, and I think I'm going to be back there. Maybe more night matches, some more excitement for the crowds, some more good times. You know, I definitely believe that. I hope it comes true next year."