Being labelled a quitter was unwarranted, Novak Djokovic [Images] said on Friday.

The Serbian, who defends his title at this week's ATP event in Indian Wells, was criticised for pulling out midway through the fourth set of his Australian Open [Images] quarter-final against Andy Roddick [Images], citing heat exhaustion.

Temperatures above 40 degrees Celsius in Melbourne made playing conditions uncomfortable but Djokovic was slammed for pulling out because it was not the first time he had done so.

In 2006, Djokovic retired after losing the first two sets of his French Open quarter-final against Rafa Nadal and in 2007 he quit during his Wimbledon [Images] semi-final against Nadal, blaming a blister on his toe.

The 21-year-old said he feels the criticism is unjust.

"It certainly isn't pleasant when something isn't right and people are talking about something which isn't true, but I'm tired of proving whatever I need to prove."

"I'm just playing tennis for myself and I always have put my health as a priority to everything. Tennis is probably my life at this moment, but it's not the only thing in my life.

"It's just that this reputation which has been going around, I don't think it's right. But everybody has a right for their own opinion."

Djokovic changed his racket at the end of last year and admitted he had struggled in the first few months of 2009.

"This was quite a big decision for me," he said.

"It took really quite some time to get used to the new racquet. I was patient and waiting, just waiting for my chance.

"I was playing quite good in [the] Australian Open but unfortunately I had to withdraw from the tournament.

"But overall, since the start of the season, I played much better in the last two months. [Winning the title in] Dubai [Images] [last month] gives me a lot of self confidence now and belief.

"I think I've proven to myself that I still have a lot of quality and I can do well."

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