Smith coy on opening change after Head heroics

Australian stand-in Test captain Steve Smith has not weighed into conversation around a batting order shuffle despite Travis Head's barnstorming Perth innings to give the hosts a 1-0 lead in the best of five series.

Trying to comprehend the innings from teammate Head, who blasted a century in just 69 balls and finished with 123 off 83 deliveries to help Australia home after offering to open, Smith said it was "too early" to consider a switch for the second Test in Brisbane that begins on December 4.

"Let's just digest this first, the last couple of hours have been pretty incredible," Smith told the press after the match's conclusion on Saturday evening.

"It's probably too early to say anything on that, but what we just witnessed was quite incredible. I'm glad to have been in the house to see it.

"We didn't like how things functioned in the first innings with Marn (Marnus Labuschagne) going up top and me batting three. So Trav took it on and played one of the great Ashes knocks."

It was the first time Head had opened the batting in Test cricket in Australia, replacing Usman Khawaja who continued to struggle with back spasms first felt on day one.

The decision to deploy Head proved a masterstroke, countering England's all-out pace attack that had put the tourists in a winning position, turning the Test match on its head and towards a rare second-day conclusion.

Not only does victory put the hosts into a strong position to retain the Ashes urn and claim another home series, it keeps their record unblemished thus far in the new World Test Championship cycle, having completed an away series clean sweep in the Caribbean earlier in the year.

In spite of the team's success, a lack of runs at the top of the ordered has fuelled questions surrounding the batting order.

Thirty-eight-year-old Khawaja's fitness on top of poor form means the left-hander's role could well be reconsidered, while debutant Jake Weatherald works his way into Test cricket.

As Weatherald compiled 23 in his second innings as a Test cricketer, contributing in a significant partnership with Head in Australia's chase, Khawaja remained off the field having reaggravated his back while outstretching for a catch in the slips during his side's bowling effort.

"He was reasonable this morning," Smith added in regards to Khawaja's fitness earlier in the day.

"I actually thought it was his knee at one point. Fortunately, it was the same thing (back issues). He (Khawaja) said before that it's probably one of the best back spasms he's ever had given the circumstances (of Head's century)."

With time to consider Australia's second innings approach, Smith admitted the timing of Khawaja's first issues and the laws surrounding his permitted re-entry into proceedings had made it hard to make a decision in the heat of Ashes battle on day one.

Khawaja eventually walked out to bat at No.4 in Australia's innings, though was dismissed for just two.

"(It) wasn't ideal, it all happened pretty quickly," Smith said. "I got told, I think just before we got the last wicket ... that he needed to be on the field to go and bat.

"There was nothing out of whack there by any stretch. Unfortunately, he just pulled up a bit lame early in the game. 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. So I can feel his pain right now."

There is no official news regarding Josh Hazlewood's hamstring ahead of the second Test, though Pat Cummins has revealed that he could return for the second Test in Brisbane as he manages his back injury.

"It's on track and pulling up pretty well. (I'm) half a chance for the next game," Cummins said on the Fox Sports telecast on day two.

"I'm pretty hopeful and it's probably better than it was a few weeks ago."