MELBOURNE (Reuters) – For all his heavy metal tennis, big-serving Milos Raonic relies on a quiet head on his shoulders during times of trouble, as was the case when beating Stanislas Wawrinka in the Australian Open fourth round on Monday.

The Canadian 13th seed looked serene as he moved two sets ahead against the Swiss former champion but even when Wawrinka roused himself to level the match, Raonic called on his Zen-like inner peace and refused to panic.

Sitting tranquilly on his court-side chair staring into the middle distance, the 25-year-old re-focused on the task in hand and completed a 6-4 6-3 5-7 4-6 6-3 victory to book a quarter-final spot.

“I felt very clear in what I needed to do and I believed that I could do it,” Raonic, who pounded down 24 aces and hit 82 clean winners, told reporters.

“I think that gave me some kind of calm and some kind of peace inside. The more I understand my game, what I need to do, the more I can keep a quiet head on my shoulders.”

Raonic, who reached a career-high of world number four last year before suffering foot and hip injuries, is one of the sport’s deep thinkers.

His mental maturity was first noted when he reached the fourth round of the Australian Open in 2011, having come through qualifying, and it continues to serve him well.

As does the attention to detail that means Raonic is always seeking marginal gains to add to one of the game’s most destructive serve/forehand combinations.

He recently added Spanish former world number one Carlos Moya to his entourage to work with long-time coach Riccardo Piatti as he bids to win the grand slam title many have predicted, but which has proved elusive.

Needless to say, just an hour after beating Wawrinka for the first time in his career, Raonic was already plotting a path past flamboyant and unpredictable Frenchman Gael Monfils — the polar opposite of himself.

“My mind’s already on what’s the process for my next challenge,” he said. “It’s very much an internal match for me.”

Raonic is on an eight-match winning run this year and had clocked up 19 consecutive sets before Wawrinka’s fightback.

While his serve remains one of the most efficient in tennis — he won 80 percent of points on his first delivery — Raonic’s volleying skills are vastly improved.

He came to the net 83 times against Wawrinka, one of the best passers, winning 54 points.

Moya has encouraged him to volley more, devoting much more time in practise to net play.

“It was something definitely I felt was necessary,” he said. “Carlos is sort of telling me keep getting yourself up there.

“He’s sort of organising my weapons.”

(Reporting by Martyn Herman, editing by Ed Osmond)