NEW YORK — Roger Federer easily won his delayed first match at the U.S. Open on Tuesday, also marking his first Grand Slam victory since losing in the second round at Wimbledon.
The Swiss great needed just 93 minutes to beat Grega Zemlja in straight sets. Federer defeated the 62nd-ranked Slovenian 6-3, 6-2, 7-5 in a matchup postponed from Monday night because of rain.
He had 12 aces and 35 winners and won 20 of 21 points at the net.
The 17-time major champion is seeded seventh this year, his worst placement since 2002.
Jerzy Janowicz, who reached the semifinals at Wimbledon, was done in straight sets, too. But his U.S. Open is over.
The 14th-seeded Pole felt as if a knife were stabbing him in his right side every time he tried to serve. After hurting his lower back Saturday, he lost 6-4, 6-4, 6-2 to qualifier Maximo Gonzalez.
Ranked 247th, the 30-year-old Argentine hadn't won a main draw match on the ATP Tour since April 2011.
"I couldn't jump," Janowicz said. "I couldn't make a service movement. It's still better than yesterday."
He had a painkiller injection Monday, which allowed him to rotate so he could hit his backhand. But he described his serve during his match as "a push." At one point in the third set, he even tried one underhand.
Janowicz took an injury timeout in the second set for a trainer to massage his back.
Janowicz had never been past the third round at a major tournament before his run at Wimbledon, which ended with a loss to eventual champion Andy Murray. The combustible 22-year-old fell in the first round at Flushing Meadows last year in his only previous appearance in the U.S. Open.
He had 11 double-faults and 53 unforced errors Tuesday.
On the women's side, fourth-seeded Sara Errani posted a "double bagel," beating Olivia Rogowska 6-0, 6-0 in 51 minutes. The 151st-ranked Australian was a "lucky loser," falling in qualifying but making the main draw when Ayumi Morita withdrew because of injury.
Seventh-seeded Petra Kvitova weathered another tough U.S. Open match, needing three sets and nearly two hours to beat 92nd-ranked Misaki Doi. Kvitova won 6-2, 3-6, 6-1 on a windy day at Arthur Ashe Stadium.
Kvitova has reached at least the semifinals at the other three major events; she has never made it past the fourth round at Flushing Meadows.
"I like big matches on the big stadium, but the people — it's too much crowds for myself, I think," she said.
She's also struggled in the North American swing leading to the U.S. Open, but she made a breakthrough last year. Kvitova won two of those tournaments and reached the semifinals at another in 2012, then matched her longest run at the year's last Grand Slam tournament.
The final set Tuesday was closer than the score in this rare matchup of two lefties. After Kvitova went up a break at 2-0, Doi had a chance to break right back but couldn't convert.
Two years ago, Kvitova became the first reigning Wimbledon women's champion to lose her first U.S. Open match in the same season. She was in danger of another early exit Tuesday when she made 15 unforced errors in the second set.
But she's hardly fazed by three-set matches. Kvitova recently played six straight across three tournaments, winning four of them.
Doi, from Japan, fell to 0-4 against top 10 opponents.
Players in action later Tuesday include top-seeded Novak Djokovic and two-time Australian Open champion Victoria Azarenka.
Sixth-seeded Caroline Wozniacki, with boyfriend Rory McIlroy in the stands, held off qualifier Duan Ying-Ying to win 6-2, 7-5.
The 133rd-ranked Duan had a chance to serve out the second set at 5-3 in her Grand Slam debut. But the 2009 U.S. Open finalist broke back. Then Duan had a set point on Wozniacki's serve that she couldn't convert. Wozniacki broke serve in the next game, then staved off three break points to clinch the win.
No. 10-seeded Roberta Vinci, a quarterfinalist at Flushing Meadows last year, beat Timea Babos 6-4, 6-2. She's reached a career-high ranking this summer at age 30 after making the round of 16 at the French Open and Wimbledon.
No. 13-seeded Ana Ivanovic and 14th-seeded Maria Kirilenko got off to quick starts, each winning in under an hour. Ivanovic, the 2008 French Open champ, beat Anna Tatishvili 6-2, 6-0. Kirilenko won 6-1, 6-1 against Yanina Wickmayer, a semifinalist at Flushing Meadows four years ago whose ranking has fallen to 57th.
Christina McHale, a 21-year-old from Englewood Cliffs, N.J., snapped a five-match losing streak by beating 45th-ranked Julia Goerges 6-4, 6-3. McHale's ranking had slipped to 114th.
On the men's side, Americans John Isner and Sam Querrey reached the second round. Isner, seeded 13th, beat Filippo Volandri of Italy 6-0, 6-2, 6-3. The 26th-seeded Querrey defeated Guido Pella of Argentina 7-6 (3), 4-6, 6-1, 6-2.
Milos Raonic won his first Grand Slam match while seeded in the top 10. The Canadian defeated qualifier Thomas Fabbiano of Italy 6-3, 7-6 (6), 6-3.