Australia's selectors face "some challenging conversations" over the next couple of days as they debate whether to retain Usman Khawaja for the final Ashes fixture after his stunning return to Test cricket in Sydney.

Khawaja scored twin hundreds in the match, his first Test for two-and-a-half years, after replacing Travis Head, who had tested positive for Covid-19. Head scored 152 in the first Test at the Gabba and is all but assured of returning, meaning that the spotlight has turned to Marcus Harris at the top of the order, and Khawaja potentially taking his position.

The selection panel, headed by George Bailey, has been big on loyalty and stability - something Khawaja said he supported - and Harris made an important 76 on the toughest pitch of the series at the MCG just two Tests ago. But Khawaja's claims are difficult to ignore.

"That was just a phenomenal performance from Uzzy," Tony Dodemaide, the newest member of the selection group, said. "Having said that, there is a lot of conversations to be had over the next couple of days. It's a very difficult one. Obviously, it's a great place to be when there's so much competition for places.

"I think what we also remember too is Marcus probably played the most consequential innings of the game in Melbourne. It's always a balance… it's very different batting at the top of the list compared to batting at five. And Uzzy said that himself. So there's certainly some challenging conversations for us over the next 48 hours or so."

Dodemaide, who said he was confident Khawaja could open if required, also hinted that it may not be just a straight call between him and Harris. "I think as selectors you need to consider all the options," he said. "That's probably the benefit of having three sets of eyes that can sit around and just have the 'what-if scenarios'.

"I guess there's any number of left field suggestions you come up with, and I think perhaps what George has said, and I agree with as well, is that let's not just think of the obvious."

Beyond the decision around Khawaja, the selectors will assess how the pace bowlers pulled up after their efforts in Sydney. Scott Boland needed painkillers after injuring his ribs when he fell in the crease on the third day, while Mitchell Starc is the only frontline pace bowler to have played every Test of the series so far, and Cameron Green's 153 overs in nine first-class matches is the most he's bowled in a season.

Starc's record with the pink ball - 52 wickets at 18.23 - will make him very difficult to leave out, and Green, who balances the side, is coming off his best innings of the series. Josh Hazlewood has already been ruled out of the last Test, but Jhye Richardson, who took a five-wicket haul in the Adelaide Test before picking up a leg injury, and Michael Neser are waiting in the wings if required.

"We've got a little bit of time, so we'll get a full report tomorrow," Dodemaide said. "The guys also have the training session as well, just to see that everyone can shake off that soreness."

One of Bailey's key philosophies since taking over as the national selector from Trevor Hohns has been to bring the selectors closer to the players, so when tough calls are made there is an understanding of why and clear communication, and also making key decisions well ahead of the games.

"They know him from being a team-mate and an opponent over the past few years, but also that he is so open with all the players and that perhaps hasn't been the case previously for maybe a number of reasons," Dodemaide said. "It's certainly a style that I'm really happy with. I want to help assist George as much as possible and get to know the players so that they have confidence in what the rationale is from time to time.

"Sure, there'll be disappointments as well, that's the nature of the game."

Andrew McGlashan is a deputy editor at ESPNcricinfo