NEW YORK (AP) The latest on the U.S. Open (all times local):
The U.S. Open is the only Grand Slam tournament where Petra Kvitova has never reached the semifinals. She has never even been to the quarterfinals at Flushing Meadows. Says she's not a big fan of all the hustle and bustle of the place.
That might be so, but the two-time Wimbledon champion had zero problems in the first round Tuesday night, needing about an hour for a 6-1, 6-1 victory over 126th-ranked Laura Siegemund, a qualifier from Germany.
Kvitova, seeded fifth, arrived in New York coming off a hard-court tuneup title in New Haven, Connecticut, and looked good in the final match of the U.S. Open's first round.
Andy Murray was only briefly troubled by Nick Kyrgios in the most-anticipated match of the U.S. Open's first round.
The third-seeded Murray, who won the title at Flushing Meadows in 2012, hit 18 aces and saved 11 of 14 break points en route to 7-5, 6-3, 4-6, 6-1 victory over Kyrgios on Tuesday night.
Murray was mostly steady in the face of Kyrgios' various antics, which included appearing to take a nap during changeovers, smashing his racket and earning a warning from the chair umpire for cursing aloud.
Kyrgios has drawn a lot of unwanted attention lately, stemming from his trash-talking to Stan Wawrinka during a match in Montreal last month. Kyrgios was caught by courtside microphones making a comment about Wawrinka's girlfriend, earning a fine from the ATP, which also put the 20-year-old Australian on six months' probation. That warning applies only to ATP events, though; Grand Slam tournaments such as the U.S. Open are sanctioned by the International Tennis Federation.
Even for Nick Kyrgios, this was unusual.
At changeovers while dropping the first two sets of his first-round U.S. Open match against Andy Murray, Kyrgios - a talented and attention-grabbing 20-year-old Australian - leaned back in his chair and rested his head, looking as if he might be ready to take a nap.
He apparently never did fall asleep, though, because he kept playing, well enough to take the third set and force a fourth.
More players have stopped playing during matches because of injuries or illness during the first round of the U.S. Open than in any round at any Grand Slam tournament in the professional era.
With the temperature topping 90 degrees, a total of 12 men and women have retired during matches Monday and Tuesday at Flushing Meadows - with the first round still yet to be finished.
The previous mark for most retirements during any round at any major was nine at the 2011 U.S. Open.
Among the 10 men and two women pulling out so far were five retirements Tuesday: Marcos Baghdatis, Ernests Gulbis, Thanasi Kokkinakis, Aleksandr Nedovyesov and Marina Erakovic.
Roger Federer gives credit where credit is due.
The 17-time major champion says several past opponents helped him become the player he is.
Federer mentioned Andre Agassi and Lleyton Hewitt as the first to force him to improve.
Those two ''really made me feel like a bad baseliner to an extent, until I realized I had to move better and be more consistent, have variation in my game,'' Federer said after his first-round victory at the U.S. Open on Tuesday.
Federer picked up pointers on serve-and-volley tactics from Pete Sampras and Tim Henman, for example.
And more recently, Rafael Nadal made Federer's backhand better.
''Rafa challenged my backhand the most throughout my career,'' he said. ''I had to return differently every single time I played against him.''
Victoria Azarenka's been known to flash a temper on court - and it happened again during her first-round victory at the U.S. Open.
This was the testy exchange Tuesday at Louis Armstrong Stadium that Azarenka, a two-time Australian Open champion and two-time U.S. Open runner-up, had with chair umpire Aurelie Tourte:
Azarenka: ''Have you ever played tennis?''
Azarenka: ''You did? You probably weren't very good.''
After beating Lucie Hradecka 6-1, 6-2, Azarenka put on a show for the spectators, bringing one girl out of the stands and handing her a racket, then rallying for a bit.
Second-seeded Roger Federer routed Leonardo Mayer of Argentina 6-1, 6-2, 6-2 in the first round of the U.S. Open on Tuesday.
Federer saved the lone break point he faced and was done in a brisk 77 minutes. The 34th-ranked Mayer had given the 17-time Grand Slam champion trouble in their only previous meeting, when Federer saved five match points to win in three sets in Shanghai last year.
Federer arrived in New York after winning his 87th career title at Cincinnati, where he posted back-to-back victories against Andy Murray and Novak Djokovic.
For the second straight day, a professional tennis player was serving at the U.S. Open by just casually swinging the racket overhead. After Vitalia Diatchenko was forced to eschew the jump serve against Serena Williams on Monday night because of a foot injury, Australian teen Thanasi Kokkinakis found himself in the same position because of cramping on a steamy Tuesday afternoon.
In his U.S. Open debut, the 19-year-old Kokkinakis was in position to pull off an upset, leading 12th-seeded Richard Gasquet two sets to one, when his legs started to cramp in the fourth.
With Kokkinakis barely able to move and serving underhand at times, Gasquet clinched the fourth set then won the first two games in the fifth before the 71st-ranked Australian had to retire, with just enough energy left to smash his racket.
Kokkinakis' name has been all over the news in recent weeks for some off-court matters. After his buddy Nick Kyrgios defeated French Open champ Stan Wawrinka in Montreal on Aug. 12, a courtside microphone picked up Kyrgios saying that Kokkinakis had slept with a player who reportedly is now Wawrinka's girlfriend. Kyrgios was fined and faces a provisional suspension.
Down two sets and a break, American Donald Young rallied to stun 11th-seeded Gilles Simon in the first round of the U.S. Open on Tuesday.
The 68th-ranked Young won 2-6, 4-6, 6-4, 6-4, 6-4 in 3 hours, 34 minutes with a packed Court 17 urging him on.
The 26-year-old Young's career has been one of extremes, a one-time teen prodigy who has stumbled through some long losing streaks as a pro. He reached his second ATP final at Delray Beach in February, dropped nine straight tour-level matches from March through August, then upset sixth-ranked Tomas Berdych in Montreal this month.
Young had never before come back to win after losing the first two sets.
''I was almost ready to go home there,'' he told the crowd in an on-court interview.
''I had nothing to lose,'' Young added of how he started going after his shots in the third set. ''He was kicking my butt.''
Simon had been 5-0 against Young. The Frenchman lost in the opening round for the first time in nine appearances at Flushing Meadows.
American John Isner got off to an impressive start at the U.S. Open, beating Malek Jaziri of Tunisia 6-2, 6-3, 6-4 in the first round Tuesday.
The 13th-seeded Isner never faced a break point in winning in a swift 1 hour, 43 minutes against the 81st-ranked Jaziri. Isner had 24 aces and 54 winners.
Isner earned his 10th career title this summer when he won in Atlanta for the third straight time. He also reached the final in Washington.
Isner's best showing at the U.S. Open was reaching the 2011 quarterfinal.
Caroline Wozniacki got herself quickly off the court on a scorching day at the U.S. Open.
The fourth-seeded Dane, last year's runner-up, beat NCAA champion Jamie Loeb 6-2, 6-0 in 67 minutes Tuesday in the first round, never in danger of becoming another upset victim on the women's side.
The 20-year-old Loeb earned a wild card into the draw by winning the college title as a sophomore at North Carolina. She made her Grand Slam debut after recently turning pro.
After Wozniacki's win, seeded women were just 12-9 so far. Add in Maria Sharapova's withdrawal, and 10 of the 32 seeds are already out before the second round.
Just four seeded women's players lost in the first round last year. Since the tournament started seeding 32 players in 2000, the largest number of women's seeds to lose in the opening round was 10 in 2012.
Sixth-seeded Lucie Safarova, who was upset earlier Tuesday, said she was bothered by a strained abdominal muscle on her right side that she hurt in losing the New Haven final Saturday. Safarova is pulling out of doubles, where she and American Bethanie Mattek-Sands would have been among the favorites after winning the Australian and French Opens this year.
Half of the top 10 seeds in the women's draw are already out of the U.S. Open.
The second day of the tournament started just like the first, with sixth-seeded Lucie Safarova the one getting upset this time. The French Open runner-up had a tough first-round matchup against 37th-ranked Lesia Tsurenko and lost 6-4, 6-1 in just 65 minutes Tuesday.
Seventh-seeded Ana Ivanovic, eighth-seeded Karolina Pliskova and 10th-seeded Carla Suarez Navarro were all eliminated Monday, a day after third-seeded Maria Sharapova withdrew because of a leg injury.
Safarova had defeated Tsurenko in straight sets in New Haven just four days earlier. She went on to lose a three-setter to Petra Kvitova in the title match Saturday.
Tsurenko had been playing well on the hard courts this summer to reach a career-best ranking this week. The 26-year-old from Ukraine upset Pliskova to make the New Haven semis, where she fell to Safarova. Before that, she upset Wimbledon runner-up Garbine Muguruza in advancing to the quarterfinals in Toronto.
The U.S. Open is the only major tournament at which Safarova has never reached the quarterfinals. The Czech lefty took Serena Williams to three sets in the French Open final.
Second-seeded Simona Halep avoided the upset bug Tuesday, moving on in 47 minutes when Marina Erakovic retired in the second set. Halep was leading 6-2, 3-0.
That adds to the seven retirements Monday, which the ITF said matched the Open era record for the most in one day at a major.