Novak Djokovic has said that he felt "very good" during his victory over Dominic Thiem at the O2 Arena in London this afternoon.
The new world number two began his ATP World Tour Finals campaign with a three-set victory over the Austrian, coming from behind after losing the opening set.
However, Djokovic does not believe that the dropped set was down to him playing badly and was pleased with his performance on the whole.
"It felt very good. Even though I lost the first set, I thought I didn't do too many things wrong. It was just the very high quality of his game that prevailed," he told reporters.
"I knew after that the first couple of games of the second set would be crucial for me to start with a break up, which I did. I felt more comfortable. I started swinging more freely in the second set. Obviously I made him play an extra shot. He started making more errors, which I used.
"I was on top of his second serves, putting a lot of pressure. I thought I played very well in the second set especially, but the third as well."
Djokovic has won the season-ending tournament in each of the last four years.
