Super-fit Andy Murray kept his cool on a brutally hot Melbourne Day to ease through to the third round of the Australian Open.

Murray, who undergoes a tough off-season training program every year in Miami, proved far too good for Portugal’s Joao Sousa, winning 6-2 6-4 6-4.

“You need to be the one that’s trying to dictate the points in these conditions,” said Murray, the No.3 seed and reigning US Open champion.

“Miami is the perfect preparation.

“It’s hot and humid there, although it certainly doesn’t get up to 37 degrees.”

Murray advanced to a third-round clash with regular practice partner Ricardas Berankis.

The Lithuanian qualifier needed only 77 minutes to send No.25 seed Florian Mayer tumbling out of the Open.

Mayer – who hammered an out-of-sorts Bernard Tomic in the pivotal match of last year’s Davis Cup playoff tie against Germany – was trounced 6-2 6-3 6-1 by Berankis.

French crowd pleaser Jo-Wilfried Tsonga also moved into the third round with a minimum of fuss.

Tsonga – whose best grand slam result came when he reached the final at Melbourne Park in 2008 – proved too good for Japan’s Go Soeda, winning 6-3 7-6 (7-1) 6-3 in two hours and three minutes.

The No.7 seed was broken early in the second set, but was able to get back on level terms and then breeze through the tiebreaker.

No.13 seed Milos Raonic from Canada beat Czech Lukas Rosol 7-6 (7-2) 6-2 6-3 to set up a third-round clash with German No.17 seed Philipp Kohlschreiber, who beat Israel’s Amir Weintraub 6-2 7-6 (7-4) 6-4.