Milos Raonic had trouble at the baseline, but still earned his first U.S. Open victory.

The Thornhill, Ont., native overcame 55 unforced errors including 15 double faults on Tuesday to defeat Santiago Giraldo of Colombia 6-3, 4-6, 3-6, 6-4, 6-4.

Raonic, the No. 15 seed, earned his 34th victory of the season in a match that lasted well over three hours.

Nestor, Mirnyi upset in doubles play

Toronto's Daniel Nestor and partner Max Mirnyi of Belarus were upset their first-round men's doubles match with American wild-cards Steve Johnson and Jack Sock 1-6, 7-6 (7-4), 6-2.

The 39-year-old Nestor had not lost this early at Flushing Meadows since 2005, a year after lifting the title with former partner Mark Knowles.

Nestor and Mirnyi, the top-ranked team, converted on three of 15 break point chances in just under two hours while losing serve twice after a runaway win in the opening set.

"That's what happens when you let a team hang around for too long," said Nestor. "This should have been over in two sets.

"I just cannot explain how our level dropped so much and without any reason after that 6-1 first set. This is really hard to take, I can't explain it."

"I'm just happy with the outcome and that I managed to make the most of that moment and just find a way to win," said Raonic. "Everything else I've got to hope gets better in the next round."

Raonic had 30 aces, but struggled with unforced errors and converted on only a third of his dozen break points.

"I don't think I struggled with my serve that much in a long, long time. A lot of double faults, and it wasn't just one double fault per game," said Raonic. "I double-faulted consistently a couple times in a row, and that made my job a lot more difficult and it gave him a little bit more freedom at the same time."

Raonic did not play at the U.S. Open in 2011 as he recovered from hip surgery. In 2010 as a qualifier, he was beaten by Australian Carsten Ball in his debut at a major.

On Tuesday, Raonic found himself down 2-1, but tied the match with a break in the final game of the fourth set as Giraldo fired wide.

The match finished with a Raonic break of Giraldo on a forehand error from the Colombian.

He will play Paul-Henri Mathieu of France for the first time in the second round of the tournament.

The biggest upset in either singles draw occurred in the night session, with former world No. 1 and 2009 U.S. Open runner-up Caroline Wozniacki driven out in two comprehensive sets.

Irina-Camelia Begu of Romania, the 96th ranked player in the world, defeated the Dane 6-2, 6-2.

The eighth-seeded Wozniacki failed to make it out of the first round of her second straight Grand Slam tournament/

Wozniacki quit after the first set of her semifinal match last Friday in New Haven, a tournament she had won the four previous years. 

Djokovic wins match in 73 minutes

Defending champion Novak Djokovic lost the first game Tuesday then ran off 18 of the next 19 en route to a 6-1, 6-0, 6-1 win over Paolo Lorenzi of Italy in the first round of the U.S. Open.

Second-seeded Djokovic won 79 of 114 points and finished with seven aces and 32 winners compared to zero and 10 for his opponent.

The match took only 73 minutes.

After Lorenzi won the first game of the third set, he raised his hands in mock victory and got a nice hand from the crowd. But that was it. He won the same number of games he did to start the Grand Slam season, in a 6-2, 6-0, 6-0 loss to Djokovic in the first round of the Australian Open.

The one-sided night play on Ashe continued when Serena Williams advanced to the second round, defeating CoCo Vandeweghe 6-1, 6-1 in 55 minutes.

Coming off wins at Wimbledon and the London Olympics, Williams looked sharp, committing only nine unforced errors.

In search of her 15th Grand Slam title and fourth U.S. Open championship, Williams improved to 48-1 in first-round matches at Grand Slams.

Vandeweghe, who fell 7-5, 6-3 to Williams in the Bank of the West Classic final earlier this summer, had trouble dealing with her toss in the blustery wind. She finished with six double faults and only held serve once in seven tries.

Andy Roddick served 20 aces to defeat 21-year-old American qualifier Rhyne Williams 6-3, 6-4, 6-4

Roddick, seeded 20th, won the last 16 points on his serve and finished the match with a 204-kilometre ace.

It was a tough way to make a Grand Slam debut for Williams, the NCAA runner-up in 2011, who won three matches in qualifying, then learned he had a first-round matchup with the 2003 champion.

Williams, ranked 289th coming into the week, put in a respectable performance, but dropped a break in each set. He'll still earn $23,000 US as a first-round loser in the year's final Grand Slam.

Sixth-seeded Tomas Berdych advanced to the second round of the U.S. Open with a straight-set win.

Berdych beat 56th-ranked David Goffin of Belgium 7-5, 6-3, 6-3. The 21-year-old Goffin had reached a career-high ranking after making the round of 16 at the French Open and the third round at Wimbledon. He was making his U.S. Open debut.

Berdych, the 2010 Wimbledon runner-up from the Czech Republic, has never been past the round of 16 at Flushing Meadows.

Goffin converted just 2-of-18 break points. Berdych had 17 aces and 40 winners.

Guillermo Garcia-Lopez rallied from down two sets and a break to upset 10th-seeded Juan Monaco.

The 68th-ranked Spaniard won 3-6, 1-6, 6-4, 7-6 (6), 7-6 (3) in just over 4 ½hours. Garcia-Lopez overcame 75 unforced errors.

With the players on serve at 3-2 in the fifth set, there were four straight breaks. Each held serve after that to force the tiebreaker.

Monaco led 4-1 in the third set before Garcia-Lopez won five straight games to win the set. It was the first time in his career Garcia-Lopez came back from down two sets to win a match.

Polish star dominant in opener

Second-seeded Agnieszka Radwanska needed just 54 minutes to advance to the second round,  beating Nina Bratchikova of Russia 6-1, 6-1 at Arthur Ashe Stadium.

The 91st-ranked Bratchikova had 28 unforced errors to only six for Radwanska.

The Polish star is coming off her first Grand Slam final, a three-set loss to Serena Williams at Wimbledon. She has never made it past the fourth round at Flushing Meadows. Radwanska retired from her previous match with a sore shoulder while trailing qualifier Olga Govortsova in her opener at New Haven.

Bratchikova was making her U.S. Open debut, but reached the third round at the Australian and French this year.

Venus Williams overcame an early deficit for an easy win in her return to the U.S. Open.

The seven-time Grand Slam champion pulled out of the tournament before her second-round match last year because of an autoimmune disease. Williams was back Tuesday, and she beat fellow American Bethanie Mattek-Sands 6-3, 6-1.

Williams, unseeded with a ranking of No. 46, was broken in her first game. But after going down 0-2 in the first set, she won 12 of the last 14 games.

Mattek-Sands is ranked 212th after a series of injuries this year and got in on a wild card.

At age 32, Williams has been learning to deal with the effects of Sjogren's syndrome, which causes exhaustion and joint pain.

Sixth-seeded Angelique Kerber moved on easily to set up a second-round match with Venus.

The German beat Britain's Anne Keothavong 6-2, 6-0 in 54 minutes Tuesday. Keothavong, ranked 81st, had 25 unforced errors to Kerber's nine.

Ranked outside the top 100 at the start of 2010, Kerber is now a career-best sixth. She reached her first Grand Slam semifinal at Flushing Meadows last year.

In other results:

  • Nicolas Almagro (11), Spain, def. Radek Stepanek, Czech Republic, 6-4, 6-7 (5), 6-3, 6-4.
  • Stanislas Wawrinka (18), Switzerland, def. Sergiy Stakhovsky, Ukraine, 6-7 (6), 7-6 (2), 6-4, 6-2.
  • Sam Querrey (27), United States, def. Yen-hsun Lu, Taiwan, 6-7 (4), 6-4, 6-4, 7-5.
  • Julien Benneteau (31), France, def. Olivier Rochus, Belgium, 7-6 (1), 6-2, 6-3.

Women

  • Sara Errani (10), Italy, def. Garbine Muguruza, Spain, 6-3, 6-7 (6), 6-1.
  • Dominika Cibulkova (13), Slovakia, def. Johanna Larsson, Sweden, 6-7 (5), 6-2, 6-0.
  • Roberta Vinci (20), Italy, def. Urszula Radwanska, Poland, 6-1, 6-1.
  • Sloane Stephens, United States, def. Francesca Schiavone (22), Italy, 6-3, 6-4.
  • Andrea Hlavackova, Czech Republic, def. Klara Zakopalova (24), Czech Republic, 6-4, 6-4.
  • Ayumi Morita, Japan, def. Monica Niculescu (26), Romania, 6-3, 6-3.
  • Olga Govortsova, Belarus, def. Tamira Paszek (29), Austria, 6-3, 6-4.
  • Jelena Jankovic (30), Serbia, def. Kateryna Bondarenko, Ukraine, 6-1, 6-2.
  • Elena Vesnina, Russia, def. Peng Shuai (32), China, 7-6 (5), 6-1.
With files from The Canadian Press