Novak Djokovic has criticised Australian teenager Bernard Tomic after he admitted he had not given 100 per cent at the Shanghai Masters, but said he had the talent to become a top player.
Nineteen-year-old Tomic said on Tuesday he had tried only "85 per cent" in his 6-4 6-0 first-round defeat to Germany's Florian Mayer, saying the pressures of the gruelling tennis tour were taking their toll.
His Shanghai flop came just weeks after he was branded "disgraceful" by Davis Cup team captain Pat Rafter following his US Open defeat at the hands of Andy Roddick.
US tennis great John McEnroe said Tomic seemed to give up during his 6-3 6-4 6-0 loss to Roddick in the second round at Flushing Meadows.
"To be honest, I don't think it's a great answer. But he will learn," said the world No.2, referring to the post-match comments Tomic made about not giving his all in Shanghai.
"I'm sure that he loves this sport. I know him well, maybe more than other guys. I know he's talented. He truly loves the sport and has high ambitions.
"It's good to be confident, but also be modest, be aware of your abilities and also try to have results before you start speaking in the media (about) different things."
Tomic, who stands 196cm tall and turns 20 this month, reached last year's Wimbledon quarter-finals but has struggled in recent months, slipping from a career-high of 27th to 43rd in the rankings.
But Djokovic said his young rival had time on his side and the weapons to succeed, provided he worked hard and was dedicated despite the pressure of high expectations from a sport-hungry public in Australia.
"It's always difficult at that age to try to figure out what you need to do in order to improve, in order to get better. He's still very young," said the 25-year-old five-times grand slam winner.
"But I believe that with time he's going to get necessary experience to understand himself better and the life that he has.
"He's also a tall guy, has a big serve," added the Serbian. "So he can be one of the top players. It's just a matter of obviously him believing in that and also working hard."