Roof plays into Djokovic's hands

The defending champion needed just 90 minutes to defeat fellow Serb and childhood friend Viktor Troicki 6-3, 6-1, 6-3 on Monday to reach the quarter-finals.

He can now rest until Wednesday while Germany's number 31 seed Florian Mayer and French 18th seed Richard Gasquet, one of whom will tackle the top seed in the last eight, were toiling in the rain out on Court Three.

They were unable to finish their last 16 clash and will try again on Tuesday with Mayer, without a win over Gasquet in eight years, leading 6-3, 2-1.

"For somebody that plays all the tournament outdoors and comes to the Centre Court for the first time and plays indoors in totally different conditions, it's quite a change. So you need time to adjust," admitted Djokovic.

Novak Djokovic. Photo: AFP

"When the roof is closed, I find it a bit easier to return serve. Obviously when you're playing on grass against a big server like Viktor, under these conditions you can neutralize the serve and get more into the rallies, so that was good for me."

Djokovic added that with the roof on, the conditions are slower, a factor he is getting accustomed to now that he has played and defeated Ryan Harrison, Radek Stepanek and Troicki with the roof shut.

In contrast, Gasquet and Mayer have played all their matches on outside courts.

"There is a difference in the speed of the ball that travels through the air. I think it's a bit slower than what is played outdoors," explained Djokovic.

"I talked with Viktor. This was his debut under the roof here, and he said it's much slower than his previous matches.

"So for me I kind of got used to it. I played only the first match outdoors, and then all the three next ones were under the closed roof. So it's a bit more humid. The balls get a big bigger."

Six-time champion Roger Federer also made the last 16, defeating Xavier Malisse 7-6 (7/1), 6-1, 4-6, 6-3 in a match which was halted for rain at the end of the first set.

However, despite dampness in the air and the temperature dropping to 15 degrees, the £80 million roof stayed open for Federer.

"I was happy they kept it open because it is an outdoor tournament at the end of the day," said the Swiss, whose hard-fought five-set win over Julien Benneteau on Friday was played under cover.

"We don't want to play indoors all the time. It's not that big of a deal coming on and off. I know spectators would rather see a match than sitting in the rain."