Djokovic, the winner of this month's lead-up Adelaide International, beat the unseeded Thai 6-3, 6-4, 5-7, 6-1 and will face either world number one Roger Federer or Russian 25th seed Mikhail Youzhny in the fourth round.

 The fast-rising young Serb served for the third set but was broken by Danai, taking the match into a fourth set.

 But Djokovic hit back with three service breaks to run through the set and take the match in two hours 45 minutes.

 Djokovic, unbeaten in eight matches this season, heads into his likely match against Federer with victories over Nicolas Massu, Feliciano Lopez and Udomchoke.

 "It was not as easy as it looked and I was serving for the match in the third set," 19-year-old Djokovic said.

 "But I made a lot on unforced errors and Danai was playing really well.

 "I gave him one chance and he seized the opportunity."

 Djokovic, who won his third career ATP title in Adelaide in the first week of the new season, said he was looking to play his best tennis to give himself a chance of a mighty upset over Federer.

 "I will really try to play my best tennis against him. I've lost both times I played him, but I won a set, so it's okay," he joked.

 Djokovic lost in three sets to Federer in their last meeting in the Masters Series in Monte Carlo last year.

 Danai, who won gold in the Asian Games singles final in Doha last month, knocked out 2003 French Open champion Juan Carlos Ferrero in the previous round and gave a good account of himself against Djokovic Friday.

 Danai teamed up with Djokovic in doubles at the Thailand Open several years and said they were good friends.

 "We played doubles one time in the Thailand Open, he's a good friend of mine but now he is going up the rankings a lot. He is a good player and very tough to beat him," Danai said.

Agence France Presse