NEW YORK (Reuters) - Defending champion Sloane Stephens eased into the quarter-finals of the U.S. Open with a 6-3 6-3 victory over Belgian Elise Mertens on Sunday.
Stephens, who has not dropped a set in four matches at Flushing Meadows this year, lost to Mertens at the Cincinnati warm-up last month but was never in danger of suffering a repeat as she wrapped up the win in one hour and 26 minutes.
"(Mertens) beat me two weeks ago so I knew that I had to come here and fight and do my best," Stephens said in. "I played a solid match so I couldn't really ask for any more."
The American struck 17 winners and controlled play from the baseline, ran relentlessly to extend the points, dominated in the longer rallies and was also helped by her opponent's struggles on serve.
Overall, Mertens won just 46 percent of her first serve points and faced nine break points, losing five of them.
Stephens by comparison won 73 percent of her first serves and saved four of the six break points she faced, while also making 10 fewer unforced errors than her opponent.
Next up for Stephens, who at number three is the highest seed left in the women's draw, is a repeat of last year's quarter-final against Latvian Anastasija Sevastova.
(Reporting by Simon Jennings; Editing by Peter Rutherford)