Novak Djokovic has responded to Rafael Nadal usurping him at the top of the world tennis rankings by beating the Spaniard in straight sets to retain the China Open title.

Nadal's semi-final victory over Tomas Berdych on Friday ensured that he will reclaim the world number one spot for the first time since July 2011.

However, Djokovic produced a serving masterclass in Beijing to exact some revenge on the man that beat him for the US Open last month and win the tournament for the fourth time in five years.

The Serbian gained an early advantage by breaking Nadal at the first opportunity, and then held to love three times on his way to taking the first set 6-3.

Djokovic then firmly established his dominance in the contest by breaking in the opening game of the second, after the scores had been at deuce on three occasions.

With the way that the six-time Grand Slam champion was serving, it was always going to be difficult for Nadal to mount a comeback, and Djokovic went on to clinch the match with an ace, dropping only six points on his own serve throughout in a 6-3 6-4 victory.