ANDY MURRAY admitted his fitness training is beginning to pay off after he survived the blistering heat to secure a straight sets win over Spaniard Fernando Verdasco in the Australian Open here today.

The British No.1 has been hampered in past matches by a lack of stamina, but he handled the heat well at the Vodafone Arena to overcome Verdasco 7-6 (7-4), 7-5, 6-4 and set up a third round meeting with Argentina's Juan Ignacio Chela.

"It was really tough today," a breathless Murray said. "The conditions were very warm and my feet were burning.

"I would rather be playing indoors. It's (the heat) really tough. It takes a lot out of you. But I've done a lot of fitness training and I'm hoping that it pays off in these conditions."

World No.16 Murray lost his serve three times in the opening set, but broke back each time and took the tie-break to put himself in command.

The 19-year-old Scot also trailed 4-1 in the second set, but hauled himself level and went on to take the set, clinching it after Verdasco had received treatment for blisters.

Murray paid tribute to a gutsy if erratic opponent who gifted too many points in the conditions to pose a serious threat.

"He did a lot of running and he has a great serve and forehand," said Murray. "There were a lot of rallies and it was difficult, but I had great support and that helped pull me through."

Murray kept his nerve in the third and, after Verdasco had saved four match points, he sealed a scrappy but reasonably comfortable second round victory.

Chela, who beat Murray in the first round in the Scot's maiden Melbourne appearance last year, promises to present Murray with a much stiffer challenge in the last 32.

He beat 17th seed Jarkko Nieminen 6-3, 2-6, 6-4, 6-4 to set up the third round meeting with the Dunblane ace, who gained revenge on Chela at the Paris Masters on carpet with a 7-5, 6-0 victory.

"He is a really good player who just missed out on a seeding here so it's going to be really difficult.

"He plays very well in these conditions and beat (Lleyton) Hewitt last year.

"I know it's going to be tricky but if I play to my best and have the support of the crowd maybe I can win this time."

Murray's older brother, Jamie, lost 6-4, 6-2 in the doubles first round with German Benjamin Becker to French pair Julien Benneteau and Nicolas Mahut.