NEW YORK (AP) - Aside from one long, long game, Novak Djokovic kept things quick on a 90-degree afternoon at the U.S. Open on Friday.
The defending champion at Flushing Meadows dropped a 24-point, 15-minute game early in the second set, a tiny blip along the way to wrapping up another easy victory to reach the third round. He beat 112th-ranked Rogerio Dutra Silva of Brazil 6-2, 6-1, 6-2.
"Definitely doesn't feel great, spending 15 minutes for one game in this heat,'' Djokovic said.
Nevertheless, Djokovic finished with more than twice as many winners, 29, as unforced errors, 14. He needed a little more than 90 minutes all told to make sure he would keep intact his record of never having lost to a player ranked outside the top 100 at a major tournament.
"I didn't know much about my opponent. Never saw him play. So that could have been, you know, a difficulty at the start in order to figure out what his game plan is,'' Djokovic said. "But I have played well from the start to the end.''
The second-seeded Serb has lost a total of seven games through two matches this year at the U.S. Open.
"Obviously, I want to spend (as little) time as possible on the court,'' Djokovic said. "I have played a lot of tennis, a lot of matches, through the course of this summer.''
That includes a runner-up finish to Rafael Nadal at the French Open, and a semifinal loss to eventual champion Roger Federer at Wimbledon, following a title at the Australian Open in January.
Dutra Silva, who never has reached the third round at a Grand Slam tournament, was impressed by Djokovic's play in Arthur Ashe Stadium.
"It's tough to hurt him. I tried, many ways, to hurt him. And actually I can't do that,'' Dutra Silva said with a smile. "I tried to play baseline. I tried to hit and hit the ball. I tried to play fast. It's so tough.''
Djokovic won 37 of 41 points on first serves and never faced a break point all match.
Dutra Silva said that while Djokovic's first serves were hard to handle - the Serb did hit six aces - it was what happened once the ball was in play that was more problematic.
"When I put the ball in the court,'' Dutra Silva said, "I was in big trouble, you know?''
Fourth-seeded David Ferrer pulled out a 14-12 tiebreaker to cap off a straight-sets victory over Igor Sijsling of the Netherlands in the second round of the U.S. Open.
Ferrer defeated the 78th-ranked qualifier 6-2, 6-3, 7-6 (12).
In a year in which Spain's top player, Rafael Nadal, is absent because of injury, Ferrer was still the fourth man from that country to advance to the third round, with two others - Tommy Robredo and Guillermo Garcia-Lopez - playing their second-round matches later Friday.
Ferrer saved three set points in the third to get off the court in 2 hours, 7 minutes on an 88-degree afternoon in the Grandstand stadium.
The 30-year-old Spaniard made the third round at Flushing Meadows for the eighth straight year.
Former champion Juan Martin del Potro beat American Ryan Harrison in four sets to reach the third round.
The seventh-seeded Argentine won 6-2, 6-3, 2-6, 6-2 on Friday. The 20-year-old Harrison, ranked 61st, was seeking to reach the third round at a Grand Slam event for the first time.
Each player faced 10 break points, but del Potro converted seven to three for Harrison.
Harrison had 42 unforced errors.
Del Potro, who beat Roger Federer in the 2009 final, couldn't defend his title the next year after right wrist surgery. Del Potro lost in the third round last year.
In women's action, No. 3 seed Maria Sharapova won 12 of the last 13 points of her match Friday to defeat NCAA runner-up Mallory Burdette 6-1, 6-1 and advance to the fourth round of the U.S. Open.
Sharapova, who completed the career Grand Slam earlier this year at the French Open, needed only 58 minutes at 90-degree Arthur Ashe Stadium to wrap up the win over Burdette, who will be a senior at Stanford this year.
Sharapova has not been tested so far this year at Flushing Meadows, losing a total of seven games over her first three matches.
Since winning the U.S. Open in 2006, this is only the second time Sharapova has advanced to the round of 16.
Defending champion Sam Stosur was pushed for the first time in the Open by American Varvara Lepchenko, but dominated the second set after winning the first in a tiebreaker.
The seventh-seeded Stosur won 7-6 (5), 6-2 in the third round. She had dropped just five games through her first two matches.
It was still a successful Open for the 31st-seeded Lepchenko. After reaching at least the third round in three straight Grand Slam events, she'll likely climb into the top 30 in the rankings.