Marnus Labuschagne is forever blowing bubbles and, over the last few weeks, scoring Test hundreds.

With a skip down the pitch at Mitchell Santner he deposited the ball over long-on, for just the second six of his career, to reach his third century in three innings following his scores of 185 in Brisbane and 162 in Adelaide. The 25-year old is only the third Australian batsman to manage such a feat after Charles Macartney in 1926 and Don Bradman in 1937-38.

"I got within one shot and I wanted to do it because scoring was quite slow so I was waiting for the right ball," Labuschagne said at the post-day press conference. "I didn't get all of it but luckily enough for it to go over."

He is a batsman with a few idiosyncrasies and a close watch will show he is rarely without his chewing gum. It has become an integral part to his batting routine since he started playing for Glamorgan - a time when runs flowed and propelled him into the Ashes squad.

"It started it in the second game of the County Championship last year," he said. "It was something I used because at times you play so much cricket and you need something to get you going and to get you in the contest. It's helped me to relax especially when I'm subconsciously blowing bubbles and keeping my mind at rest between balls."

There were no free runs on offer on the opening day in Perth, so full focus was needed. Without taking anything away from his runs against Pakistan, that was not always the case in the first two Tests of the summer. In this innings his first fifty took 102 balls, with Australia well behind their usual scoring rate, before moving to three figures off a further 64 deliveries. It was the innings of a player who can be at No. 3 for a long time to come.

"You never want to take any runs for Australia for granted," he said. "Cricket can be a tough game so you have to cash in when you're doing well. No hundred comes easy, but today there were patches where scoring really dried up completely and you just had to trust you would come out the other side

Before the Test, Tim Paine revealed there had been conversations about moving Labuschagne down the order to No. 5 to allow him to settle into Test cricket after being thrust back into the team during the Ashes.

"He didn't want a bar of it," Paine said. "He wanted to go out at three. He wants to be a star Test match international cricketer. He sees himself as a No.3. He wants that challenge. He'd be hard to move out of there now, that's for sure."

Labuschagne recalled a slightly different tale from the Brisbane Test when, with David Warner and Joe Burns having added a double-century stand, Justin Langer suggested - perhaps in jest - that he may want to slip down the order having spent so long waiting with his pads on.

"Justin asked me at the 'Gabba, because we waited so long to bat and you burn a lot of mental energy. He said do you want to go down? I kind of laughed as in 'you're kidding, aren't you?' I still don't know if he was serious, but I thought there's no chance I'm letting [Steven] Smithy bat in front of me. I enjoy getting out there; sitting and watching can be draining."

Batting is coming easily for Labuschagne at the moment, but he believes being in good form brings a need to be even more careful. "It's just about riding the wave, not trying to get too high when you are going well. Keeping a clear mind on the field then you just play the ball as it comes. People say you nick balls more when you are in form because you a seeing it so well so it's about keeping a high price on decision making."

At the moment, he's making a lot of good decisions. He'll hope the run-scoring bubble doesn't burst anytime soon.