Stan Wawrinka’s close friend Roger Federer once likened him to a diesel truck – slow to warm up but almost unstoppable once he got going.

The description proved apt in their Australian Open semi-final, with Federer forced to fight tooth and nail for a five-set win after his Swiss compatriot roared to life in the second half of the match.

Federer’s 7-5 6-3 1-6 4-6 6-3 triumph on Thursday night was his 19th career win over Wawrinka but just the first to go to five sets in their 22 matches together.

That prospect had looked far from likely, with fourth seed Wawrinka outclassed by a clinical Federer in the early going.

Already down a set, Wawrinka’s frustration boiled over when he handed Federer a service break and a 4-2 lead in the second.

The burly 31-year-old threw his racquet to the ground and then broke it in half over his knee, earning a code violation.

With Federer taking the second set, Wawrinka left the court almost in tears to have his knee strapped.

He looked a different man when he returned, winning 20 of a possible 26 points in the third set and dominating on serve to take the fourth.

But Federer took over in the decider, with Wawrinka double-faulting to give away a 4-2 lead and struggling to get back into the match.

A three-time champion at the majors, Wawrinka had been aiming to become the first man other than Federer, Nadal or Novak Djokovic to win back-to-back grand slam crowns since Andre Agassi in 1999-2000.

He will pocket $820,000 in prize money after downing the likes of Jo-Wilfried Tsonga and Andreas Seppi on his way to the semi-final.