Tennis: Djokovic hails new physical and mental fitness

Novak Djokovic did something he couldn't master five years ago as he cruised into the third round on another scorching day at the Australian Open Wednesday.

The three-time defending champion brushed aside Argentine Leonardo Mayer 6-0, 6-4, 6-4 in straight sets and showed few ill-effects of the intense heat which brought him undone at the 2009 tournament.

Back then Djokovic withdrew from his quarter-final with Andy Roddick trailing 7-6 (7/3), 4-6, 2-6, 1-2 in furnace-like conditions when he could not continue.

Yet five years on the Serb was in command of his opponent and adapted to the extreme conditions to keep on track for his fifth Australian title.

Djokovic said he was now physically and mentally strong enough to overcome the harsh playing conditions encountered in a Melbourne summer, in contrast to when he suffered against Roddick .

"Everything is fine. I'm physically fit. I've been practising and preparing for the Australian summer that we all know can be difficult at times with the conditions," he said.

"Obviously as the years go by I'm more matured as a player. I learn new things in life. I develop myself. I physically got stronger -- mentally also.

"It's not easy," he added. "Maybe it looks it, but I do go through tough times after long rallies, as everybody, trying to get some air.

"Generally it's much more efficient for me nowadays to recover and to get ready for the next point than it used to be in 2009 when I retired in my match against Roddick."

It was Djokovic's 23rd straight win at the Australian Open as he bids to become only the second man after Australia's Roy Emerson to claim four consecutive Australian crowns.

It was an improved performance by the Serb after his sloppy first-round effort against Slovakia's Lukas Lacko on Monday.

He broke the tall Mayer's service five times and did not face a break point on his own serve. He also hit 30 winners to just 11 unforced errors while pressuring Mayer into 39 errors.

"I started the match really well. I was set and a break up only after 40-45 minutes," Djokovic said.

"You don't want to spend too much time in the heat. You want to try to win as quick as possible.

"He started to play better as the match progressed but I felt like I was serving well and I was in the control. It was a better performance than the first round."

His next opponent is Uzbekistan's Denis Istomin, who got past Russian 30th seed Dmitry Tursunov in four sets.