US Open: Caroline Wozniacki powers past Sara Errani

Wozniacki was the first Dane to reach a Grand Slam final in the Open Era, losing to Kim Clijsters in the 2009 US Open

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.

Peng has been number one in the doubles rankings

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.

Thiem (left) lost on his 21st birthday to sixth seed Berdych

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."

Cilic hit 23 aces, 70 winners and committed 76 unforced errors in the 4hr 13min clash with Simon

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."

All Tuesday's results

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."

Hingis (left) and Pennetta face third-seeded Cara Black and Sania Mirza for a place in the final

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."

Simon had never lost to Cilic before their last-16 meeting