US Open 2015: Roger Federer & Petra Kvitova reach fourth round

Roger Federer swept past Kohlschreiber to set up a last-16 meeting with John Isner of the United States

Five-time US Open champion Roger Federer put in a commanding performance to beat Germany's Philipp Kohlschreiber to reach the US Open fourth round.

Second seed Federer lost his serve for the first time since Wimbledon but still easily won 6-3 6-4 6-4.

In the same half of the draw, fellow Swiss Stan Wawrinka and Britain's Andy Murray also progressed.

Second seed Simona Halep of Romania and fifth seed Petra Kvitova both won in straight sets.

Halep beat American qualfier Shelby Rogers 6-2 6-3, while Kvitova routed Slovak Anna Karolina Schmiedlova 6-2 6-1 to secure a last-16 meeting with Briton Jo Konta.

Konta, 24, beat German 18th seed Andrea Petkovic 7-6 (7-2) 6-3 to extend her remarkable winning run to 16 matches.

The British number two had never been past the second round at a Grand Slam before this week.

Roger reveals the 'Fed Attack'

Federer beat world number one Novak Djokovic in straight sets in the Cincinnati Masters final in August

Since recruiting Stefan Edberg to his coaching team in December 2013, Federer has varied his game with more approaches to the net to counter the baseline prowess of the likes of world number one Novak Djokovic and Britain's Andy Murray.

However he revealed he stumbled on his recent habit of advancing in behind his return almost by accident during a jet-lagged practice session with Frenchman Benoit Paire during August's Cincinnati Masters event.

Federer explained: "I said, 'OK, I'm going to chip and charge and just keep the points short. I'm tired. I want to get off the court soon anyway.' That's when I started to run in and hit returns. I hit a couple for a winner. They were ridiculous.

"I tried it the next practice and it still worked. That's when coach Severin Luthi said, 'Well, what about using it in a match?' I was like, 'Really?'

'We sort of came up with that name, 'sneak attack by Roger' or 'Sabr' for short. I don't know. Call it 'Fed Attack', call it whatever you want."

Azarenka enjoys 'heat of battle'

Azarenka was a runner-up at the US Open in 2012 and 2013, losing to Serena Williams on both occasions

Former world number one Victoria Azarenka beat German 11th seed Angelique Kerber 7-5 2-6 6-4.

The Belarusian 20th seed converted her sixth match point to end one of the best matches of the tournament on Arthur Ashe Stadium.

Azarenka is a two-time finalist but battling her way back up the rankings after two years interrupted by injuries.

"It's probably the most you can miss when you're an athlete, not just a tennis player. That intensity, that feeling of the battle, heat of the moment. Personally that's what I live for."

What a Gas...

Gasquet has won 15 out of 16 matches against Australian opponents

Richard Gasquet secured his spot in the fourth round by beating Australian Bernard Tomic in straight sets, 6-4 6-3 6-1.

The shot of the match came when a thick net cord allowed Frenchman Gasquet to play a winner around the net post and he continued running to receive a congratulatory fist bump from Tomic on his opponent's side of the net.

"Bernard is a great friend of mine so I think I can do it with him," said Gasquet about the fist bump. "You don't do it with guys you don't like."

Gasquet will play Czech Tomas Berdych, who beat Spain's Guillermo Garcia-Lopez 6-7 (2-7) 7-6 (9-7) 6-3 6-3.

Swiss fifth seed Stan Wawrinka saw off Belgian Ruben Bemelmans 6-3 7-6 (7-5) 6-4, while American 13th seed John Isner led Jiri Vesely 6-3 6-3 when the Czech retired with a neck injury.

Britwatch

In the men's doubles, Scotland's Colin Fleming and Treat Huey of the Philippines overcame Australia's likely Davis Cup team of Lleyton Hewitt and Sam Groth 6-3 6-4.

Fleming and Huey, who had never played together before the US Open, will face Leonardo Mayer of Argentina and Portugal's Joao Sousa in the next round.

Quotes of the day

"My voice feels like normal again. Still dull, obviously." Andy Murray is over the head cold he was suffering and back to his normal self.

"Between 'finish' and 'punish', he came up with 'pinish'". Victoria Azarenka reveals that hitting partner Sascha Bajin has been inventing a new motivational language to help her.

"It was 90% you guys, 10% me. I was on the other end of one of those against Andy Murray in Scotland so it is nice to have you guys 100% for me." American Donald Young, who was beaten in four sets by Murray in the Davis Cup in Glasgow in March, revels in the home-crowd support after coming from two sets down to beat 22nd seed Viktor Troicki of Serbia.

"For the coffees I'm going out, but otherwise I'm staying in the room." Petra Kvitova is taking a simple approach to her pre-match preparation.

"I have done mistakes when I was younger, you know. Playing video games until too late and feel tired the next day." Roger Federer reveals his past misdemeanours.

Maria Sharapova, missing from the tournament with a knee injury, is keeping the US Open's official Twitter feed honest.

Selfie of the day

A small night out in the Big Apple - Novak Djokovic, wife Jelena and coach Boris Becker hit the town