The Serb, using the HEAD Racquet Rebel, finished 2015 with a decisive 6-3, 6-4 defeat of Roger Federer to become the first to win an unprecedented fourth straight title at the Barclays ATP World Tour Finals.
The London triumph further enhanced the reputation of Djokovic, who endorses the HEAD Graphene XT SPEED.
It was the eighth meeting of Djokovic and Federer in 2015, with the HEAD player now leading 5-3.
Djokovic says: “This season could not have been better.
“It has been the best of my life.
“I’m trying to enjoy every moment on court and cherish competing at such a level.
“When you are growing up, this is what you are dreaming of – competing for the biggest trophies in the sport.”
