US Open: Dominic Thiem and Alexandr Dolgopolov reach fourth round

World number eight Dominic Thiem reached the fourth round of the US Open in 2016

Sixth seed Dominic Thiem registered a straight-set win over Adrian Mannarino to reach the US Open fourth round.

The Austrian beat the French world number 34 7-5 6-3 6-4.

Mannarino served for the first set but sent a volley wide, allowing Thiem to break, and then lost seven games in a row as he struggled for rhythm.

Thiem, who has reached the quarter-finals at Flushing Meadows three times in the past four years, will play Juan Martin del Potro in the next round.

The Argentine beat Spain's Roberto Bautista Agut 6-3 6-3 6-4 to set up the meeting with Thiem.

Del Potro said: "I think that bottom half of the draw is going to be surprising for one guy.

"But in the top half, you have Roger and Rafa, Dominic, as well, and they are favourites to win a Grand Slam title, for sure."

• Nadal fights back to beat spirited Mayer

• Fognini thrown out of US Open for outburst

• World number one Pliskova saves match point to beat Zhang

• Live scores, schedule and results

Dolgopolov plays down gambling controversy

Ukrainian Alexandr Dolgopolov also reached the fourth round with a speedy win over Serbia's Viktor Troicki.

Dolgopolov won 6-1 6-0 6-4, hitting 24 winners and dominating with his first serve to win in just one hour and 21 minutes.

This is the 28-year-old's best run at a Grand Slam since he reached the quarter-finals of the Australian Open in 2011.

Dolgopolov needed only 82 minutes to beat 52nd-ranked Troicki

He will face Spanish world number one Rafael Nadal in the last 16 on Monday.

Dolgopolov, whose defeat by Thiago Monteiro at the Winston-Salem Open is being investigated by the Tennis Integrity Unit, said the scrutiny was not affecting his performance.

"If people want to write something, they write something. You can't stop them from doing it. It's just not under my control," he said.

"You can see I'm playing. I'm fit. I'm doing well."

Belgian ninth seed David Goffin advanced to the fourth round after his opponent Gael Monfils retired with an injury to his right knee.

Goffin, who reached the fourth round at Flushing Meadows for the first time, was leading 7-5 5-1 when the French 18th seed quit.

Goffin next faces Russian Andrey Rublev for a place in the last eight.