Nadal advances at slick Cincinnati

Rafa Nadal urged tournament organisers to make more consistent surfaces for hard court events after easing past American Taylor Dent 6-2, 7-5 to make the third round of the Cincinnati Masters on Wednesday.

The Spanish world number one came back from 4-2 down in the second set to defeat 83rd-ranked Dent but was unhappy that he had to adjust to a much faster court than last week's surface in Toronto.

"It is something (that) in the future the tournaments can work to make the courts more similar," Nadal told reporters.

"For us it's difficult to adapt, especially if you only have one or two days. When you get to semi-finals or final it's not easy to adapt, especially in the beginning of the tournament.

"So it's big change. This first match always is very dangerous," he added.

After struggling in the first set, journeyman Dent's serve improved noticeably in the second and he threatened to make life complicated for the Spaniard when he broke him to take a 4-2 lead.

But Nadal broke twice to go 6-5 up before serving out the match to set up a third-round encounter with Frenchman Julien Benneteau, who defeated Switzerland's Stanislas Wawrinka in straight sets.

Roger Federer went through after his Uzbeki opponent Denis Istomin had to retire with an ankle injury when 5-2 down in the first set.

He was joined by third seed Novak Djokovic and fourth seed Andy Murray as the form book proved a reliable guide despite none of the leading players truly sparkling.

Murray needed three sets to deal with France's Jeremy Chardy, losing his rhythm after winning the opening set 6-3 as his aggressive opponent mixed 53 unforced errors with 44 winners.

The Scot lost the second set tiebreak 7-3, but won the third 6-2 after the Frenchman took a medical time-out for foot treatment.

Murray agreed that it was tricky to switch to the high-speed court.

"It can be difficult. You don't have a whole lot of time to get used to the conditions here. They're very different. The court's much faster than Toronto and the balls are moving a lot quicker.

"When you are feeling like that, it's kind of difficult to really go for your shots a lot. But I knew I had to in the third set, and played a lot better," he added.

Spain's Fernando Verdasco was the only surprise victim, losing to 36th-ranked American Mardy Fish.

Fish, who has credited his recent surge in form to weight loss, entered the tournament on a wildcard but played some inspired attacking tennis to beat Verdasco in two tiebreaks.