Pascal Siakam scored 25 points to lead Indiana's scoring. Tyrese Haliburton added 15 with nine assists and Myles Turner had 17 points as six Pacers players scored in double figures.
On the brink of elimination after an embarrassing game five defeat in New York, the Pacers played with desperate aggression, out-scoring the Knicks 62-38 in the paint and winning the rebounding battle.
They hustled after loose balls, blocked eight shots and handed out 35 assists to keep their offense firing, and kept Knicks talisman Jalen Brunson in check for much of the night as they improved to 6-0 at home in this post-season.
They'll have to follow up on the road, however, if they want to book a clash with the Boston Celtics in the Eastern Conference finals, with the Knicks hosting game seven on Sunday at Madison Square Garden.
"Now it's a one game series, and it's for all the marbles," Haliburton said. "Where better to have a game seven than the Garden?
"No team's won a game on the road in this series, so we've got to be ready to go from start to finish in 48 minutes."
The Pacers broke open a close game with a 17-2 scoring run that pushed their lead to 13 points late in the second quarter.
Donte DiVincenzo stopped the rot for New York, draining a three-pointer from the corner that cut the Pacers' lead to 10, 61-51, at halftime.
Brunson was limited to five points on 2-of-13 shooting in the first half. He found his range after the break, scoring 14 points in the third and finishing with 31.
Miles McBride added 20 for the Knicks, whose brief surge to open the third quarter was quickly squelched by the Pacers.
"There really isn't any excuse for anything," Brunson said. "Just the way they played tonight you've got to give them credit."
Pacers coach Rick Carlisle said it was a matter of playing harder.
He said Siakam, an NBA champion with Toronto in 2019 and acquired from the Raptors in January, had provided a key veteran presence on a young and a crucial skillset that made a big difference on Friday.
"He's the only guy on our roster that can manufacture a 16-foot shot over a seven-foot guy and make it," Carlisle said. "He did it three or four times in the third, fourth quarter."
While Carlisle was pleased with his team's bounce-back win, he was already looking ahead to the test awaiting on Sunday.
"In a series like this, you can't sit around patting yourself on the back. That's what gets your ass kicked the next game," he said.
Physical, mental test
The Knicks return home with yet another injury concern after forward Josh Hart departed early in the fourth quarter with what the team called abdominal soreness.
He'd clearly been troubled by discomfort around his midriff since the first quarter.
It's just the latest blow for the Knicks, who saw forward OG Anunoby go down to a hamstring injury in game two after they were already without Julius Randle, Bojan Bogdanovic and Mitchell Robinson.
"We'll see," was head coach Tom Thibodeau's tight-lipped response on whether Hart would be available on Sunday, but he made it clear the Knicks wouldn't be citing injuries as an excuse.
"This is the nature of the play-offs," he said. "This is what you play for. Oftentimes it comes down to a hustle play, a loose ball .. so you're going to get tested physically, mentally, emotionally - and you've got to be able to get through all of that.
"So whatever it is that we're facing, we can overcome and just keep battling."
