"Well, he might not serve as hard as he did probably when he won the U.S. Open in 2010," Djokovic said. "I think that was the hardest he served ever in his career on hard courts, actually. But now he's using the serve very efficiently. He's going for precision. He knows that he can back it up. He has one of the best second shots in the game. That's why he doesn't feel as much maybe pressure and that's why he's more relaxed and he can have a lot of variety.
"He's a lefty, which is advantage because he doesn't get to play many lefties.Well, majority of the players are righties, and he can have this great slice and open up the court. He's been playing well, no question about it. He's confident, and he's very dangerous opponent on any surface."