Cheteshwar Pujara absorbed 11 blows to the helmet, hands and body in a stonewalling innings of 56.
Rishabh Pant was more aggressive, mixing scoops, sweeps and slogs on his way to an unbeaten 89.
Together, they ushered India to a famous victory — retaining the Border-Gavaskar trophy with a stunning win in the fourth and final test against Australia.
Pujara needed medical treatment and a new helmet in the middle session of day five but battled for 211 balls as India chased 328 for victory at the Gabba.
Pant had stayed at the crease for 138 balls for his knock, guiding India to a three-wicket victory and hitting the winning runs with a four down the ground off Josh Hazlewood.
"I keep thinking every day that I want to win matches for India, and I did it today," Pant said after his heroics.
With the four-test series tied 1-1, India needed only a draw to retain the trophy, but they accomplished so much more, handing the Australians their first defeat at the Gabba since 1988. It had been a stunning Indian effort to turn what were once slim prospects of victory into a realistic opportunity.
News.com reports that Indian legend Sunil Gavaskar explained in commentary what the win meant to India, describing it as "India's most famous series victory ever".
"Despite the win two years ago, in their heart of hearts they would have known without David Warner and Steve Smith it would have been just that little bit easy," he said.
"Now that David Warner and Smith are there, this is the one."
Aussie legend Ricky Ponting also described what the loss means for Australia.
"You can't speak highly enough of India, it is as simple as that," he said.
"I said yesterday on air it looked like this game might be a draw and even if it was a draw, that would be a worse result for Australia than when they lost two years ago. We all sat back and said India got us when we were at our weakest without David Warner and Smith there.
"But guess what, David Warner and Smith have been there, our entire bowling brigade has been there, and India have been the exact opposite. So if Australia go on to lose this game, it will hurt, it will dig really deep."
Aussie legend Shane Warne also said the victory for India was one of the greatest Test wins in Indian cricket history after fighting back from a 1-0 series deficit and losing half of their first-string stars, including Kohli, news.com reports.
"That's as good a test match win as I can remember. I can't remember a better test match win in recent times," he told Fox Cricket.
"There'll be plenty of questions and plenty of fall out for the Australians, but let's just take a moment to appreciate India."
India resumed on day five at four without loss and added 14 before Australian paceman Pat Cummins elicited an edge from Rohit Sharma (seven) and had the dangerous opener caught behind in the ninth over.
Enter Pujara, a veteran of 80 test matches and less than a week away from his 33rd birthday. He joined 21-year-old Shubman Gill in a 114-run stand that not only helped thwart the Australian attack but also kept India in the contest for an unlikely win.
While Gill compiled 91 from 146 balls, his highest score in a three-test career, Pujara anchored down at the other end, taking hits on the body against the short ball rather than risk playing cross-bat shots in the situation.
The partnership lasted most of the first session and half of the second and was starting to accelerate when off-spinner Nathan Lyon re-entered the attack and had Gill edging to slip, where Steve Smith took a sharp reflex catch. Gill had just plundered left-arm paceman Mitchell Starc in one over that netted India 20 runs and got him within a few scoring shots of his maiden century.
India's stand-in captain Ajinkya Rahane replaced Gill and maintained a good strike rate while Pujura had plenty of dramas on 26, surviving a decision review for lbw from Lyon and a short ball from Hazlewood that crashed into the grill of his helmet and dislodged the neck guard on the back, enforcing another medical break.
The pair added 35 for the third wicket before Rahane tried a ramp shot against Cummins and was caught behind for 24 from 22 balls.
With the total at 167-3 in the 57th over, the sight of Pant walking to the crease to replace Rahane suggested India were still chasing a win.
He delivered just that.
EVERY SESSION WE DISCOVERED A NEW HERO.
— Sachin Tendulkar (@sachin_rt) January 19, 2021
Every time we got hit, we stayed put & stood taller. We pushed boundaries of belief to play fearless but not careless cricket. Injuries & uncertainties were countered with poise & confidence. One of the greatest series wins!
Congrats India. pic.twitter.com/ZtCChUURLV
The result means India move to the top of the World Test Championship rankings.
The Black Caps are at number two, and Australia are third.
The three teams are competing for a place in the championship final, to be held at Lord's later in the year.
England also remain a chance to make the final after beating Sri Lanka in the opening test of their two-test series. But they would need a remarkable 3-0 result in India to force their way into the conversation.
The Pumas held on for a 28-24 win in Dublin.