US Open: Caroline Wozniacki powers past Sara Errani
US Open, Flushing Meadows, New York
Dates: 25 August-8 September Coverage: Live radio and text commentary on Andy Murray's matches and all quarter-finals onwards, plus commentary every day from 18:00 or 18:30 BST on BBC Radio 5 live sports extra
Denmark's Caroline Wozniacki strolled into the semi-finals of the US Open with an impressive 6-0 6-1 win over 13th seed Sara Errani of Italy.
Tenth seed Wozniacki, 24, raced through the match in only 65 minutes to claim a place in the last four.
The former world number one will face China's Peng Shuai, who reached her first Grand Slam semi-final by beating Swiss teenager Belinda Bencic 6-2 6-1.
An emotional Peng, 28, said: "It's a little too exciting."
In the other quarter-finals, to be played on Wednesday, top seed Serena Williams faces Flavia Pennetta and Victoria Azarenka takes on Ekaterina Makarova.
Wozniacki, in the semi-finals of a Grand Slam for the first time in three years, said: "It means so much to me.
"It has been a pretty up-and-down year for me and to be here in the semi-final of the US Open is an incredible feeling."
Errani, a losing finalist at the 2012 French Open, failed to hold her serve once in the match as Wozniacki powered past the 27-year-old world number 14.
World number 39 Peng played a superb opening set against Bencic, breaking the 17 year old twice.
And Bencic, the world 59 who beat sixth seed Angelique Kerber and ninth seed Jelena Jankovic on her way to the last eight, was broken twice in succession at the start of the second set and was also given a violation for coaching as Peng won in an hour and four minutes.
"It's an amazing time for me," said an emotional Peng. "I love tennis but it's a long time, my career. It's been tough sometimes. I was thinking about giving up because I don't know if I can make it."
In the men's singles, 14th seed Marin Cilic needed five sets to reach the quarter-finals with a 5-7 7-6 (7-3) 6-4 3-6 6-3 win over 26th seed Gilles Simon of France.
Cilic, a quarter-finalist in 2009 and 2012, missed last year's tournament at Flushing Meadows while he served a drugs ban.
The Croat will meet sixth seed Tomas Berdych, who raced to a 6-1 6-2 6-4 victory over promising Austrian youngster Dominic Thiem in one hour and 38 minutes.
Gael Monfils beat Grigor Dimitrov 7-5 7-6 (8-6) 7-5 to set up a quarter-final meeting with five-time champion Roger Federer, a straight-sets winner over Batista Agut.
Arthur Ashe Stadium
Peng Shuai (Chn) beat Belinda Bencic (Sui) 6-2 6-1
Gael Monfils (Fra) (20) beat Grigor Dimitrov (Bul) (7) 7-5 7-6 (8-6) 7-5 - Report
Roger Federer (Sui) (2) beat Roberto Bautista Agut (Spa) 6-4 6-3 6-2
Federer said he "controlled" the game well in windy conditions and was looking forward to a quarter-final match-up with Monfils.
"The good thing for both of us is we just played in Cincinnati," said Federer. "It was a really tough match.
"Gael has been playing some great tennis; he's one of the most entertaining and exciting players out there. I'm sure we'll see lots of retrieving by him and attacking by me."
Caroline Wozniacki (Den) (10) beat Sara Errani (Ita) (13) 6-0 6-1
Louis Armstrong Stadium
Ekaterina Makarova (Rus) (4) & Elena Vesnina (Rus) (4) beat Venus Williams (USA) & Serena Williams (USA) 7-6 (7-5) 6-4
Marin Cilic (Cro) (14) beat Gilles Simon (Fra) (26) 5-7 7-6 (7-3) 6-4 3-6 6-3
"It's amazing and really important," said Croatian Cilic, who had never beat the Frenchman Simon in four previous attempts.
"I knew Gilles would not go away that easily. All of our matches were very close but eventually he was always winning."
Tomas Berdych (Cze) (6) beat Dominic Thiem (Aut) 6-1 6-2 6-4
"I'm very happy with today's win," Berdych said after ruining Thiem's 21st birthday.
"I'd like to point out one thing which was the key, when I was 0-40 down in the first game on serve, and I saved it. That was a nice boost in the beginning and from then on I played well.
"Everything worked today. Job done, that's good."
Stats of the day
Despite not winning a single service game in her 6-0 6-1 defeat by Caroline Wozniacki, Sara Errani got 82% of her first serves in - more than her opponent (71%)
But the Dane's receiving points won percentage was at 76% - winning 26 out of 34
In 2014, Dominic Thiem has risen from 139th to 45th in the world - making him the youngest player inside the ATP top 50.
Hingis back on the Grand Slam trail
Martina Hingis is in a Grand Slam semi-final for the first time since 2002 after she and Italian Flavia Pennetta beat fifth seeds Kveta Peschke and Katarina Srebotnik 6-4 6-3.
Twelve years ago, the Swiss, now 33, went on to win her last major doubles title with Anna Kournikova at the Australian Open.
"Right now it's kind of a dream coming true," said Hingis. "When I started playing again that was definitely something I was hoping for. Now with Flavia, it's becoming reality."
Quotes of the day
"I was very happy to see a lot of people even at 02:00 at night. I don't even know how they go back home." Kei Nishikori after completing his epic win over Milos Raonic at 02:26.
"Sometimes, you know, I just feel like I want a Coke." Gael Monfils on his choice of beverage at changeovers. Asked if he does yoga or any specific exercise routine to maintain his amazing flexibility, Monfils added: "Just every day thank my mum and my dad. Seriously, it's just because of them."
Grigor Dimitrov was not surprised to see Monfils giving up on service returns, appear out on his feet and yet play well enough to win in straight sets. "I don't think about that because he's been like that throughout all the matches and I think all the years."
Peng Shuai's career is remarkable in itself, given she had heart surgery at the age of 12. "At the time it was actually like quite big surgery. They said if I keep playing they worry about if I have a problem. But after the surgery I was OK to do the sport."
"The most important thing is you have to trust and rely on your partner. That's what I feel with Flavia - she's there when I'm down, she's there when some things don't always work, we're always there for each other." Martina Hingis on her doubles partner Flavia Pennetta.
A ball girl was hit by a stray ball during the warm-up between Marin Cilic and Gilles Simon, who said: "It's dangerous when you have a tennis ball in your eye.
"I just wanted to be sure she was fine because I had the feeling she just wanted to stay on the court, but it was just really hurting her. I asked her 10 times, and 10 times I had the same answer. I hope she's fine."