BEIJING (REUTERS) - World No. 1 Novak Djokovic and the man who can dislodge him from the top spot by next week, Rafa Nadal, kicked off their China Open campaign with straight set victories on Tuesday.

Defending champion Djokovic needed just 54 minutes to crush his Czech opponent Lukas Rosol 6-0, 6-3 without hitting a single double fault in a dominant first round display.

The Serb, aiming for his fourth China Open title in five years after missing the 2011 tournament through injury, went into the match with a perfect 14-0 record in the event.

Nadal had to work longer to subdue Colombian qualifier Santiago Giraldo 6-2, 6-4 in 90 minutes at Beijing's National Tennis Stadium.

The Spaniard, who needs to reach the final in Beijing to reclaim the No. 1 ranking, had no problem bagging the first set but Giraldo put up a stiffer resistance in the second before going down.

Nadal meets Philipp Kohlschreiber of Germany in the second round while Djokovic takes on Spaniard Fernando Verdasco.