As Andy Murray makes progress through the Australian Open draw in search of a second successive grand-slam title, his contests are sure to hot up in intensity and standard.

Yet when he plays the Portuguese Joao Sousa in the second round tomorrow, it will be the heat in the air that will concern him just as much as the man on the other side of the net.

Temperatures are expected to hit 39ºC (102ºF) here tomorrow: tough conditions for anyone, even someone like Murray, who trains in the heat and humidity of Florida and who is ranked 97 places above his opponent.

"You basically take on as much fluid as possible," Murray said after opening his account with a 6-3, 6-1, 6-3 win over the Dutchman, Robin Haase. "You can't leave anything to chance; you have to make sure you are well-hydrated and I probably won't spend as much time on the practice court as I normally would. On the day of the match, you've got to try to conserve as much energy in the build-up and hope your body reacts well to the heat."

The good thing for Murray is that he has played in seven previous Australian Opens and is also used to hot conditions from various stops around the Tour.

"Cincinnati's probably up there as the hottest place," he said. "The humidity there's pretty rough. As a junior, I played in Paraguay and that was the hottest. It was 43ºC/44ºC, and I think it was like 99% humidity. It was a joke. Actually, amazingly, I played Dani [Vallverdu, now his hitting partner]. The score was 6-2, 0-6, 6-4 to me. That was the hottest place I've ever played in."

At the US Open two years ago, Murray was given a huge scare when Haase came out swinging and took the first two sets before fading and losing in five.

Yesterday, the Scot started in the mood to get it over and done with, conserving energy for the tougher tasks ahead and his performance was so impressive that Haase felt the need to tell him so.

The Dutchman said: "I saw him in the locker room afterwards and I said: 'Well done with the first set'.Because the way he started off – and I actually hit a lot of good second serves – the way he returned today from the start; that's the best you can get."

If he plays like that tomorrow, then Sousa is unlikely to be able to cope although the Portuguese world No.100 revealed that he had a secret weapon; Rafael Nadal's part-time coach, Francisco Roig.

"He's one of the bosses at the BTT academy where I practise," Sousa said. "So I practise with him. He helps me a lot when I am at home. I have my fitness coach at the academy, as well. In pre-season, I work with my fitness coach and I work with him all the time when I go home to prepare for tournaments."

Like Murray, Sousa was a promising footballer as a teenager, having played for Vitoria Guimaraes youth teams until the age of 14, when he chose tennis.

Murray has never played him before but said he had spotted him playing at a couple of tournaments.

"I don't know too much about him but I saw him play a couple of matches during the clay-court season last year, in Barcelona," he said. "I also saw him a little bit at the French Open, as well. But I have never practised against him and never played against him."

Murray will take nothing for granted but, with a relatively easy path to the last 16 on paper, he might be forgiven for keeping one eye on developments in his section of the draw.

Gilles Simon, the 14th seed, is the highest-ranked player in his part of the bracket but Murray will not have missed a superb performance from Gael Monfils, who beat No.18 seed Alexandr Dolgopolov in four sets of outrageous shot-making.

The Frenchman missed chunks of 2012 with chronic knee injuries that at one stage looked as though they might end his career but yesterday he ran everything down and got the better of Dolgopolov.

Should Monfils get through his next match, he is likely to play Simon, with Murray his anticipated opponent in the last 16.

The sixth seed, Juan Martin Del Potro, scheduled to meet Murray in the quarter-finals, opened up with a 6-1, 6-1, 6-2 demolition of Adrian Mannarino, of France. Del Potro has flattered to deceive since returning from a year out with a wrist injury but there are signs he is returning to his best.

A quarter-final against Murray would be the perfect stage to prove it.