Can't take anything for granted: Novak Djokovic

World No.1 tennis player Novak Djokovic has said he cannot take anything for granted and needs to work harder, keeping in mind former champion Rafael Nadal's exit from the first round of Wimbledon.

"You cannot take anything or anybody for granted. You have to be grateful for being in this position and work even harder to stay there. That's the whole point," said Djokovic after defeating German Florian Mayer 6-3, 7-5, 6-4 in the men's singles on Tuesday.

"The sport is evolving, like everything in life. Everybody is getting better, getting more professional. Especially at the opening stages of Grand Slams, there are a lot of quality players who have nothing to lose coming on the Centre Court or Court 1, playing in front of 10,000 or more people. Against one of the top players, what can you really lose? You're going and you're playing your best tennis,” Djokovic was quoted as saying by atpworldtour.com.

Nadal, a two-time Wimbledon champion, was stunned by World No.135 Steve Darcis of Belgium Monday.

“I watched the bigger part of that match and I thought that Darcis played great. Darcis came up with some incredible shots, incredible points in important moments and he deserved to win,” the Serbian said.

“I know people expect all the other top players to get to at least the final stages of a Grand Slam or whatever tournament they play. It was a surprise in the end him (Nadal)losing to Darcis, but his opponent played great.”

The Serb is aiming to win his second title at the All England Club, having triumphed in 2011 over Nadal.