Spain's Rafael Nadal struggled more than in his opening match but pulled it together in time to defeat Grigor Dimitrov 6-2, 5-7, 6-2 and set up a quarterfinal showdown with arch-rival Roger Federer at the Western & Southern Open in Cincinnati, Ohio.

Nadal broke Dimitrov's serve in the fifth and seventh games en route to an easy first-set win on Thursday evening, putting the Bulgarian on his heels with penetrating ground strokes and powerful returns.

Dimitrov then found himself close to defeat when he went down a service break at 4-3 in the second set, but he recovered it in the very next game to shift the momentum of the contest and eventually even it at a set apiece.

The first game of the third set proved critical, however, as Nadal secured his fourth service break of the match to give himself some breathing room.

He eventually got one final break in the seventh game of the final set and wrapped up the match in just over two hours.

"I played a good level in the first set. Then his serve was working well in the beginning of the second. I was having trouble, so just wait for my moment," Nadal was quoted as saying on the ATP World Tour's Web site.

"I started the third set trying to go another time inside the court and trying to have the control of the point from there, and I think I played a good third set in general."

Nadal was less sharp than in his opening match of the Cincinnati Masters on Wednesday, when he routed German Benjamin Becker 6-2, 6-2.

Next up for the third-ranked Spaniard in Friday evening's quarterfinals will be Federer, who rallied to defeat Germany's Tommy Haas 1-6, 7-5, 6-3 in the third round.

Nadal has a 20-10 career edge over the Swiss great, although they have split their 12 meetings on hard courts.

The Cincinnati Masters is one of the biggest hard-court events on the ATP Tour calendar and a key tune-up for the U.S. Open, which gets underway later this month. EFE