Wimbledon may have built its reputation on being an uniquely grass-court Grand Slam tournament but defending champion Novak Djokovic is happy to play it under a roof, with the lights burning bright.

Top seed and world No 1 Djokovic gave the Centre Court roof the thumbs up on Wednesday after beating America's Ryan Harrison 6-4, 6-4, 6-4 to reach the third round.

With the roof closed after three hours of rain had brought a halt to action on the outside courts, Djokovic was delighted to get a second chance to play the late-night entertainer.

"It's hard to prepare for that because you play an indoor match on the Centre Court maybe once every couple of years. The year 2010 was my only match under the roof aside from tonight's match," said Djokovic.

"It is quite different. I think the lights were really good. The attendance was fantastic. The crowd enjoyed it. It was a spectacular match from a player's point of view. Sometimes it's good for a change to be under the roof. It makes it more interesting as well I think, if you go to the late hours."

Djokovic's match with Harrison ended shortly before 10 pm local time and he goes on to tackle either Czech veteran Radek Stepanek or Germany's Benjamin Becker for a place in the last 16.

The Serb, who was only briefly in danger when he fought off six break points in the sixth game of the second set against the world No 48, believes he was able to adapt his game to the muggier conditions under the roof.

"It's a bit more humid, so you have to adjust your movement. The ball travels through the air a bit slower, the balls get a little bit bigger," said Djokovic.

(China Daily 06/29/2012 page22)