Spain's Rafael Nadal will be back in the No. 1 spot when the new ATP rankings come out on Monday after Tomas Berdych retired from their China Open semifinal match here Saturday with a back injury.

The Czech world No. 5 was serving down 2-4, 15-40, in the first set, which had already featured three service breaks, when he was forced to stop.

Nadal has returned to the top spot for the first time since mid-2011 thanks in large part to his dominating performance on hard courts, with Saturday's win marking his 26th consecutive victory on what was once his least favorite surface.

The Spaniard was out of action for seven months from mid-2012 until early 2013 due to a serious knee injury and illness, but has won 10 of the 13 tournaments he has played since returning to the Tour, including his eighth French Open title and his second U.S. Open crown.

Next up in Sunday's final will be Serbian top seed Novak Djokovic, who defeated Frenchman Richard Gasquet 6-4, 6-2 Saturday evening but will drop to No. 2 in the rankings even if he wins the tournament.

Djokovic wrested the No. 1 ranking away from Nadal in July 2011 and, after relinquishing it a year later to Roger Federer, grabbed it back in November 2012 and has held it since.

This will be Nadal's third stint at No. 1, having previously held the top ranking in 2008-2009 and 2010-2011.

Nadal leads the overall head-to-head against Djokovic 22-15 and has won three out of the four matches against the Serbian this year, including two wins on hard court at the Cincinnati Masters and the U.S. Open final.

But Djokovic leads their overall head-to-head on hard courts 11-7. 

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