Spain's Rafael Nadal booked a spot in the quarterfinals of the China Open with a 6-4, 7-6 (7-3) victory Wednesday over Germany's Philipp Kohlschreiber.

Nadal prevailed in a sloppy first set in which he dropped his serve twice but broke the German on three occasions.

The world No. 2 struggled right off the bat in the second set as well, but he managed to save three break points to avoid an early deficit and the two players then dominated their service games until reaching the tiebreaker.

In the "breaker," the 13-time Grand Slam champion got two key mini-breaks to take a 5-2 lead and then served the match out by winning his final two service points.

Nadal, who also struggled with Kohlschreiber in the round of 16 of this year's U.S. Open, credited the German for his strong play.

"Today the serve, in my opinion, helped in the important moments," Nadal said in the post-match press conference.

"But it's true that his level of tennis I think was just brilliant tonight. I won because I played a great match. If not, I would not be here with a victory."

Nadal, winner of 10 out of the 13 tournaments he has played since returning to the ATP Tour after a serious knee injury, including his eighth French Open and second U.S. Open titles, moved one step closer Wednesday to reclaiming the No. 1 ranking from Serbia's Novak Djokovic, who is also competing in Beijing.

The Spaniard will take back the top spot by reaching this week's final regardless of how Djokovic fares.

Next up for Nadal in Friday's quarterfinals will be Italy's Fabio Fognini, who trounced Australia's Lleyton Hewitt 6-0, 6-2 in less than an hour.

The China Open is part of the ATP Tour's post-U.S. Open Asia swing, which includes events in Malaysia, Thailand, China and Japan.