Sainz battles from hospital bed to front row in Australia after appendix surgery
The tough Spaniard missed the Saudi Arabian Grand Prix due to his medical issue and returned to his race seat at Albert Park this week with no training since the operation.
Though short of full fitness, he has barely put a foot wrong in Melbourne, and on Saturday might have ripped pole from Verstappen's grasp but for a relatively slow final sector on his last flying lap.
"I’m not going to lie I'm not in my most comfortable state when I’m driving out there but I can get it done," Sainz told reporters.
"And as far as I can get it done without pain... obviously (there is) a lot of discomfort and weird feelings, but no pain, so it allows me to push flat-out."
Sainz was the only non-Red Bull driver to win a race in 2023 when he topped the podium at Singapore.
His fastest lap in Melbourne qualifying was a quarter of a second shy of Verstappen's best but Sainz said he might have been faster if he weren't short of practice.
"I think nowadays you need to be 100% to beat Max and today I wasn't. And probably due to that, I missed out on pole," he said.
"I will give it my absolute everything to do it because it's been a while since Singapore, and he's been on that top step since.
"But yeah, if there's one weekend where we have a good pace, it's this one. Tricky track to overtake, tricky on tyres. So who knows? I think we might have a chance."
Sainz's teammate Charles Leclerc (26) qualified fifth but was promoted to fourth on the grid following a grid penalty to Red Bull's Sergio Perez (34).
Perez was third in qualifying but will start from sixth.
Leclerc topped the timesheets in the last two practice sessions but complained of balance problems during qualifying and abandoned his final run in the last session.
"All in all, not a clean qualifying," he said.
"I wasn’t really happy with the feeling of the car, but tomorrow it’s a long race.
"There are four DRS zones and from now on I’ll focus on that to try and maximise the result from where we start."