John Isner praises Novak Djokovic's returning ability

WATCH—Match point from Djokovic's win over Isner at ATP Finals:

John Isner has little doubt about where Novak Djokovic ranks as a returner.

"He's No. 1 and No. 2 and No. 3," he said. "He's the best returner I've ever faced for sure."

The 6'10" Isner in one of the biggest-serving players in tennis—both on his first and second ball—but Djokovic had few problems getting his booming delivery back in a 6-4, 6-3 win at the ATP Finals. Isner was broken three times and faced nine break points.

But the 33-year-old still enjoyed his first match at the event, and said he didn't play badly.

"It was amazing, as I said before, to play there and to play against the No. 1 player in the world. You know you're going to have a full house and a great atmosphere," he said. "I tend to play long matches, but that wasn't the case tonight. It wasn't that I was nervous or anything like that. I was embracing the atmosphere and I tried to stay as positive as I could."

Isner is the lowest-ranked player in the field.

This Week on Tennis Channel:

ATP Finals (Sun - Sun 11.11 - 11.18) - Novak Djokovic, Roger Federer and the world's best collide in the season Finale. Live coverage begins on Tennis Channel Sunday at 7:00am EST.