Travis Head may have batted himself into a permanent role as Australian opener after his swashbuckling 123 against England, casting doubt on the future of an ageing Usman Khawaja.

The 38-year-old Khawaja failed to open in either innings in Perth because of back spasms, paving the way for Head to seize the opportunity with all guns blazing.

His 123 from just 83 balls drove Australia to a crushing eight-wicket victory, with the knock hailed as one of the best in Ashes history by skipper Steve Smith.

Australia have been searching for a new opener since David Warner retired early last year with Khawaja going through six different partners.

Debutant Jake Weatherald got the nod for Perth.

But instead of striding out alongside Khawaja he padded up with Marnus Labuschange in the first innings then Head, promoted from number five in the order, in the second.

Weatherald fell for a second-ball duck first up, but did enough with a composed 23 alongside Head to warrant another crack in the second Test at Brisbane.

What happens next with an out-of-form Khawaja remains to be seen, with Smith non-committal when asked if his days were numbered.

"Let's just digest this first I think, you know the last couple of hours has been pretty incredible," he said after the game.

"It's probably too early to say anything on that.

"He's not moving particularly well in there, the old fella," he added.

"Unfortunately he just pulled up a bit lame early on in the game, and that happens when your back goes.

"I've been there myself when your back seizes up, and it's not a nice place to be."

Khawaja came under fire for playing golf on the eve of the Test, although Cricket Australia boss Todd Greenberg stressed the back problem was pre-existing.

Head said opening for Australia at home had been "brewing for a bit", having done the job several times on overseas tours.

"Played a lot of cricket with Jake (for South Australia), so I was pretty keen to take some pressure off him. I just felt like the moment was right," he said.

"I was pretty bullish around the fact that I felt like I could do it. I'm always putting my hand up.

"I'm not going really aggressive at it, but I put my hand up. If the team requires it, I'm more than happy to do it and keep the option there."