Andy Murray cruised into the quarterfinals with a comfortable 6-2, 6-2 victory over Alexandr Dolgopolov in the Shanghai Masters.

"I think I did a decent job," the U.S. Open champion said. "It's very, very different conditions to last week. I think you can see by some of the results here, the guys that have come from Beijing have adapted to the conditions much, much quicker.

"So, yeah, I just tried to stay solid and go for the lines too much early on. I tried to keep the ball low. He's very explosive when the ball's up around his shoulders. Just tried to keep the ball low, play solid, and I served well."

Murray did have one or two frustrating moments in the game, however. "I got a bit frustrated at the beginning of the second set," he said. "I had just broken serve and played a bad game to get broken back. I wanted to try and finish the match as best as I could.

"I gave away the momentum that I had and let him back into the match. So sometimes it can be better to get your emotions out and move on. I managed to do that by breaking the next game.

"Better to not let it fester sometimes and maybe let it affect you for a few games. Like I say, I got the break in the next game, so that was good."

The world number three will now take on Radek Stepanek, after the veteran defeated John Isner in three sets. "He's one of the few guys that still plays at the top of the game in singles and doubles," Murray said. "He's incredibly fit for his age. I think he's maybe 33, 34 now. He's in great shape. He's incredibly quick and flexible. He has a very different game style to a lot of the guys now.

"He's a character on the court, as well. He likes to entertain, too, and can frustrate guys. I'll need to make sure I'm focused and patient and take care of my side of the court."

The defending champion admitted he had found it a little hard to adjust to the speed of the court, after his stint at last week's Japan Open. "The conditions in Tokyo, the last few matches, it was very hot," he said. "The court here is playing quick.

"But the balls compared with last week are completely different. I think they use the same balls in Beijing, the Head balls. They use Shricksen in Japan, which they don't use on any other tournament on the tour. They're quite heavy, hard balls. These ones are pretty light.

"A lot of the matches I've watched, the matches have gone pretty quick. It feels like the court's playing a bit faster and the balls are moving quickly. I mean, I've seen a few matches that have finished in under an hour, which these days doesn't happen too often. There's been quite a lot of quick matches."