US Open: Gael Monfils through to face Roger Federer in quarters

Gael Monfils upset seventh seed Grigor Dimitrov in a feisty contest to reach the US Open quarter-finals.

The Frenchman, seeded 20th, won 7-5 7-6 (8-6) 7-5 - his first victory in the main Arthur Ashe Stadium.

Monfils is through to the last eight without dropping a set, and he will next face Roger Federer, who breezed past Roberto Bautista Agut 6-4 6-3 6-2.

Despite leading for most of the match, Monfils appeared close to losing control during a stormy second set.

At one point he appeared angry with his opponent, standing almost on the service line and beckoning Dimitrov to serve before swatting the ball out and marching to his chair.

"I just get a bit [angry]," explained Monfils.

"Then I was sorry for Grigor, because I was in front and was like, 'Just serve because obviously I give you the game, so it's OK. Move it.'

"Sometimes when I get frustrated, when I don't like [something], I don't do it. It's nothing against anyone. I was upset."

A heated conversation with the umpire was followed by gestures towards both his support team in the stands, and those of Dimitrov, but he recovered his poise to claim a surprise win.

It was a disappointing performance from Dimitrov, who made 38 unforced errors and was broken three times, double-faulting on match point.

He later played down the suggestion that his opponent's antics might have distracted him, saying: "I don't think about that because he's been like that throughout all the matches and I think all the years.

"Today I could only focus only on me, because I was just playing bad tennis.

"I actually couldn't see what's going to happen on the other side. I couldn't care less. Gael, he's a great player. He definitely found his way around the court pretty good."

There was no similar upset in the evening session on Arthur Ashe as second seed Federer eased past Spaniard Agut in just under two hours.

He said: "It was difficult and we definitely had to adjust to the wind and I'm always happy when I get through those matches".

On facing the theatrical Monfils in the quarter-finals, Federer added: "I think he's one of the most exciting and entertaining opponents out there."

Bulgarian Dimitrov had been expected to set up a first Grand Slam clash with Federer but was outplayed by, for the most part, an unusually consistent Monfils.

The 28-year-old from Paris is one of the most flamboyant players on the tour, and a regular in the daily highlights reel, but, playing without a coach in New York, he proved far more steady than Dimitrov.

A poor service game from the Bulgarian saw the first set slip by and after Monfils let a lead disappear in the second, amid his brief meltdown, Dimitrov wasted two set points with four consecutive errors to give up the tie-break.

The Bulgarian's best hope appeared to be superior fitness, built up under coach Roger Rasheed - a former employee of Monfils - but Dimitrov could not move ahead and so invited pressure.

Serving to stay in the match for a second time, Dimitrov thumped a forehand long to fall match point down and duly double-faulted to leave Monfils beating his chest in victorious celebration.