© AP Enlarge Rafael Nadal is just two wins away from becoming world No. 1 again

Rafael Nadal continues to close in on a return to the top of the world rankings after beating Philipp Kohlschreiber 6-4 7-6(3) to book his place in the quarter-finals of the China Open.

The reigning US Open champion extended his winning streak to 19 matches, a run stretching from his shock first-round loss to Steve Darcis at Wimbledon in the summer.

The Spaniard, who lifted the China Open in 2005, will become the world No. 1 for the first time since July 2011 if he reaches the final in Beijing, regardless of what Novak Djokovic does at the event.

Nadal kicked off in ruthless fashion to claim the break and race into a 2-0 lead, playing a couple of stunning forehand winners.

And the break was to be the first of four consecutive in the opening set, as Kohlschreiber managed to level the contest at 3-3.

The pair continued to hold serve until the ninth game, but it was Nadal at 5-4 in front who took three points on the spin from 30-15 down to take the first set.

There were no breaks throughout the second set, so a tiebreak was required to separate the players, and it was Nadal who asserted his authority to clinch it 7-3 and advance to the last-eight.

Eighth seed John Isner came through in three sets against Roberto Bautista Agut, but Lleyton Hewitt was beaten 6-0 6-2 by Fabio Fognini.

At the Japan Open, top seed Juan Martin del Potro eased through to the quarter-finals with a 6-2 6-2 win over Carlos Berlocq. Second seed Jo-Wilfried Tsonga was upset 6-4 7-6(5) by Ivan Dodig, as was eighth seed Janko Tipsarevic by Alexandr Dolgopolov. Third seed Milos Raonic came through 6-4 7-6(0) against Go Soeda.

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