Australia's two-wicket win in the first Test was notable for being achieved without much contribution from the prolific pair as they made 35 runs between them. That's the fewest they have put together when they have both batted twice and it remains the case even when one of them hasn't.
It is potentially a daunting prospect for England who will rue letting a match slip away when they had kept Labuschagne and Smith quiet, and maybe also for the members of Australia's coaching staff who will be feeding them balls in the nets when training does resume in London at the weekend.
"They will be no doubt a craving for more net sessions from Marn and Smudge. They're disappointed they missed out in this game, but I think any time the Australian cricket team can win without those two performing at high level is always a positive. We've got some areas we can improve, there's some growth within the team and there's two obvious ones."
It is not that Labuschagne lacks experience in English conditions. He has played here extensively and averages 55.52 for Glamorgan from 26 County Championship appearances, while he made four half-centuries in the 2019 Ashes after being Smith's concussion sub at Lord's.
His contest with Broad now looms as one of the fascinating duels of this series. Given the amount of work he puts into his batting, and his hunger for training, he will no doubt leave no stone unturned to try and find a response for the second Test while the same applies to Smith, although he came into Edgbaston on the back of a superb 121 against India.
"I genuinely just expect [Labuschagne] to score a hundred next game," he said. "We had potentially our two best batters not score runs this game. It's very unlikely, doesn't happen very often. In my opinion, the greatest batter of my era in Test cricket, Steve Smith, not very often he misses out twice. We've still got four Ashes Tests. Might be a good thing for us, they have some runs in the bank."
The coaching staff will be there to offer advice, but McDonald expects they'll work out their own solutions.
"I think there's always a curiosity to get better, so we're not going to stall that in any way," he said. "They'll come up with different plans, different movements.
"They've seen what England are going to do and how they're going to attack them, and they're probably two of the greatest problem-solvers we've had over a period of time so you would expect them to go back to the drawing board.
"[Batting coach] Michael Di Venuto will be part of that process. They'll come out pretty clear what they need to do next innings. But there's no issue there."
After two days off, Australia will begin their preparation for Lord's on Saturday. That is expected to largely be a training session for those who didn't play at Edgbaston, but it would be no surprise if Labuschagne and Smith can't resist an extra hit.