The world number two told BBC Sport: "In the third set he started to serve very well, and it was hard to get the ball back into play. I saved a couple of break points, and at 6-5 I had an opportunity and I used it. It was a great match.
"I am feeling good. I had two days off and recovered a little bit. I had a couple of tough matches last week, especially the second round against Radek Stepanek, so it was good to win this in straight sets against such a good player as Tsonga."
Djokovic won the tournament in 2011.