After a difficult year, the under-pressure 32-year-old chose the most timely moment to score his first century in any form of cricket for 11 months in Potchefstroom, just five days before Australia play their first Test in South Africa since the 2018 ball-tampering scandal.
Former skipper Ricky Ponting has led the chorus that Labuschagne's Australia place has become "untenable" after three years and 43 Tests without a Test ton, capped by three failures in the recent Bangladesh series.
Yet the South African-born batter looks sure to fill the No.3 spot once more in the first Test that starts in Durban on Friday after his swift century against a modest Cricket South Africa Invitation XI attack on Sunday.
Labuschagne was largely untroubled as he raced to a 76-ball ton, going on to 111 from 89, decorated with 19 fours, before retiring to let his colleagues also get in some batting practice on the final day of the two-day warm-up match.
They enjoyed the opportunity too, with Steve Smith also retiring after making 61 while Alex Carey, fresh from his fine form in the third ODI, hit another half-century (57) as Pat Cummins' Australian side rattled up 6-368 in the drawn procession.
Smith, who received a 12-month ban when captain for his role in altering the condition of the ball with sandpaper at Cape Town on the infamous tour eight years ago, is back with a group of other survivors from that tour - Cummins, Mitchell Starc, Nathan Lyon and Matt Renshaw, all of whom could play on Friday.
Renshaw declared he was good to go after a knock to his right wrist in the final ODI, but he missed out by being dismissed for 32 off his 50 balls, as did fellow opener Travis Head (21 off 22 balls), while Beau Webster brushed off a few cobwebs with his 42 before he retired.
All eyes, though, were on Labuschagne, who even had a bit of local support as he took the crease at Senwes Park, a venue less than 50km from where he was born in Klerksdorp and the emotional scene of his first ODI hundred for Australia back in 2020.
"Really nice. Looks like he's got a lot of energy at the crease, it's the Marn that I know that's batting well," enthused Renshaw, who gave himself a clean bill of health for Durban.
"Really nice to see him getting the runs and doing what he wants to do. Really nice positivity, his feet were moving well and he was just reacting."
And didn't the Smith-Labuschagne partnership generate a sense of safety out there? "Definitely," said Renshaw. "As in the past, it's very successful if they're both scoring out there."
Australia will see it all as a useful outing after they gave 11 bowlers a run-out on the Saturday when the Invitation XI declared on 7-318 after a century from former Proteas' captain Neil Brand.
Meanwhile, South Africa paceman Anrich Nortje is in line for a remarkable return to first-class cricket after an absence of three-and-a-half year to help the injury-hit Proteas' attack.
With fitness doubts over key strike bowler Kagiso Rabada and three others, Nortje could return to Tests for the first time since March 2023 after a series of back and hip problems that left him concentrating on white-ball formats to reduce the strain on his body.
"I'll be very excited if I can put my Test cap on again. Growing up, it's the format you want to play," he said on Sunday, the day before he's expected to be named in South Africa's Test squad of 15.
