The Latest: Querrey's win ends run of 4 losses for US men
MELBOURNE, Australia (AP) The Latest on Wednesday from the Australian Open (all times local):
It's been a disappointing day for the American men at Melbourne Park.
John Isner, the highest-seeded U.S. player in the men's draw, wasted a two-set-to-none lead and lost in the second round to Mischa Zverev of Germany, 6-7 (4), 6-7 (4), 6-4, 7-6 (7), 9-7.
Isner had 98 winners in the 4-hour, 10-minute match, but only converted one of 17 breakpoint chances against Zverev.
Isner was joined on the sidelines by Steve Johnson, Noah Rubin and Ryan Harrison - all second-round losers on Wednesday afternoon.
The one bright spot for the U.S. was 31st-seeded Sam Querrey, who advanced with a 7-6 (5), 6-0, 6-1 win over Australian wild card Alex De Minaur.
Jack Sock, the 23rd seed, was playing later against Karen Khachanov of Russia.
After winning the first two sets of his second-round match, Roger Federer had to really go to work in the third, recovering from 5-2 down and fending off two set points to defeat American qualifier Noah Rubin 7-5, 6-3, 7-6 (3).
He held serve at love to force the tiebreaker and, after it got to 3-3, reeled off the last four points to clinch the match in 2 hours, 4 minutes.
Federer is a four-time Australian Open champion but hasn't lifted the trophy since 2010. In 18 trips to Melbourne Park, he's never failed to reach the third round.
Eugenie Bouchard is back in the third round at Melbourne Park for the first time in two years, defeating China's Peng Shuai 7-6 (5), 6-2.
Bouchard, who reached the semifinals of the Australian Open in 2014, finally closed it out after Peng saved three match points on the Canadian's serve at 5-1 in the second set.
Following her break-out year in 2014, which also saw her reach the Wimbledon final, Bouchard struggled to make it past the fourth round at the slams. Her best result last year was the third round at Wimbledon.
Her next opponent will be either CoCo Vandeweghe or Pauline Parmentier, who played later Wednesday.
''Overall, I'm feeling better with each passing day,'' Bouchard said.
Fourth-seeded Stan Wawrinka is into the third round of the Australian Open for the ninth consecutive year after a 6-3, 6-4, 6-4 win over American Steve Johnson on Wednesday.
Wawrinka won his first Grand Slam title at Melbourne Park in 2014 and has followed that up with two more majors - the French Open in 2015 and the U.S. Open last year.
The 31-year-old Wawrinka labored through five sets to win his first-round match against Martin Klizan in 3 hours, 24 minutes. He had a much easier time in the second round, beating Johnson in 1 hour, 52 minutes.
Wawrinka will next play either Viktor Troicki or Paolo Lorenzi.
Defending champion Angelique Kerber marked her 29th birthday - angrily at times - with a 6-2, 6-7 (3), 6-2 win Wednesday over fellow German Carina Witthoeft.
Kerber, who beat Serena Williams in the Australian Open final last year, then won the U.S. Open in September, was her own worst enemy in the tiebreaker, double-faulting twice to turn a 3-2 lead into a 4-3 deficit.
Witthoeft, who had won a long rally which caused Kerber to swipe her racket toward the court just ahead of the double faults, won the next three points to level the match.
Kerber also started poorly in the third set, dropping her service, but rebounded to take a 4-1 lead, saving two break points in the fifth game, before closing out the match in 2 hours, 8 minutes.
She will next play the winner of Wednesday's second-round match between Kristyna Pliskova and Irina-Camelia Begu.
Serena and Venus Williams have pulled out of their scheduled first-round doubles match because of a right elbow injury to Venus, who won her singles match earlier Wednesday in straight sets over Stefanie Voegele.
The Williams sisters were set to play Timea Babos and Anastasia Pavlyuchenkova in a Show Court 2 match on Wednesday afternoon. The Australian Open confirmed the withdrawal on social media.
The American pair also withdrew from their first-round doubles match in 2015 at Melbourne Park.
The Williams sisters have won 14 Grand Slam doubles titles together, including four at the Australian Open.
Kei Nishikori advanced to the third round in a far more straightforward manner than his five-set opener earlier this week.
The fifth-seeded Nishikori defeated Frenchman Jeremy Chardy 6-3, 6-4, 6-3 in just over two hours to reach the third round for the seventh consecutive year.
On Monday, he needed 3 1-2 hours before beating Andrey Kuznetsov in the first round.
''(I) was definitely playing much better than first round today,'' he said Wednesday. ''There were many ups and downs, still too many break points for me. Great to finish in three sets.''
Nishikori has reached the quarterfinals three times at Melbourne Park, but has never advanced beyond that stage. He could play top-seeded Andy Murray in the quarterfinals this year.
Venus Williams, a first-round loser in 2016 at Melbourne Park, is one of the first players into the third round this year after beating Stefanie Voegele 6-3, 6-2 to begin play at Rod Laver Arena on Wednesday.
Williams maintained a perfect 3-0 record against the Swiss player, having beaten her on clay at Madrid, grass at Wimbledon and now hard courts in the year's first Grand Slam tournament.
Voegele wasn't helped by four double-faults in the opening set. In the second, Williams broke Voegele's service with a blistering forehand to the open court to take a 3-1 lead, then broke her serve again in the final game.
Williams lost to eventual semifinalist Johanna Konta in the opening round last year.
The older sister of Serena Williams, Venus Williams has never won the Australian Open. She lost the 2003 final to Serena. Venus' best recent finish here was a quarterfinal appearance in 2015.
Defending champion Angelique Kerber and top-seeded Andy Murray play their second-round matches on Wednesday in much more pleasant temperatures at Melbourne Park.
A cool change hit the city overnight, dropping temperatures from 38 Celsius (100 Fahrenheit) on Tuesday afternoon to about 20 Celsius (68 Fahrenheit) when play began Wednesday.
Venus Williams was first up on Rod Laver Arena, playing Stefanie Voegele of Switzerland. Kerber was to follow against fellow German Carina Witthoeft, followed by Roger Federer against American qualifier Noah Rubin.
Murray was scheduled to play the last match on Wednesday night at Rod Laver.
Venus and Serena Williams were scheduled to play their opening doubles match on Wednesday afternoon.