Defending champion Novak Djokovic has reached the final of the Shanghai Masters by beating Jo-Wilfried Tsonga in straight sets.

Djokovic, who beat Andy Murray in last year's final, booked his place in this year's main event with a 6-2 7-6 victory over the French number one.

The Serb will now face either Rafael Nadal or Juan Martin del Potro.

Tsonga started the match sluggishly and produced two double faults in his opening service game, which he lost to love.

The Frenchman broke back in game five thanks to some brilliant backhand ball-striking, including a cross-court winner on break point.

However, his joy was short lived, as he lost his next two service games, allowing his opponent to take the opening set after 34 minutes.

Djokovic broke again early in the second set, as he quickly established a 4-2 lead.

However, Tsonga immediately broke back in controversial circumstances.

At 15-40, Tsonga's backhand slice, which was initially called wide by the line judge, was deemed to have caught the line by hawk-eye.

The umpire then awarded the Frenchman the vital point, claiming that the call had been late and made after the ball had passed the Serb.

Djokovic, who had deliberately let the ball go beyond him, was furious and vented his anger at the umpire in an explosive rant during the change of ends.

Fuelled by frustration, the top seed went on to seal his passage into the final, converting his second match point to break Tsonga for a fifth time.