The 26-year-old Canadian guard made 15-of-22 shots from the floor, 4-of-5 from 3-point range, and all 11 of his free throws while adding seven rebounds, eight assists, two blocked shots and a steal in a maestro performance.
"It's the extra plays that put you over the edge," Gilgeous-Alexander said. "We have a group of guys that are hungry to do whatever it takes to win and that's why we win."
Jalen Williams added 20 points and Isaiah Hartenstein contributed 11 points and 13 rebounds for the Thunder in his 11th double-double of the season.
The Western Conference-leading Thunder are 24-5 and on a roll despite a loss in the NBA Cup final to Milwaukee that didn't count against them in the regular season.
"The main thing is it's genuine," said Hartenstein. "We're not coming in trying to fake something. We really all support each other.
"We're not trying to put something on for the TV or for the world to see. We're really supporting each other and I think that's what makes it special."
Andrew Nembhard led the host Pacers (15-16) with 23 points. Indiana took a 61-53 half-time lead before the Thunder struck in the second half and closed the game on a 17-7 run for the victory.
"We didn't get off to the start we wanted," Gilgeous-Alexander said. "But that's what good teams do, play through situations and because we did that we got the W."
Gilgeous-Alexander, who set his career high of 45 points last month in a victory over the Los Angeles Clippers, sank a 3-pointer to give Oklahoma City a 114-109 edge with 59 seconds remaining and sank six free throws in the final 36 seconds to seal the triumph.
His crucial 3-pointer came after extra work on his outside shooting and confidence to keep firing after a miss.
"It feels good, but that's what the work is about," Gilgeous-Alexander said. "It went in because I took the shot.
"In the past, I probably would have gotten discouraged missing one and not shooting it, but I would like to think I've grown a bit, enough to trust in my work, take a shot, stay true to it and it paid off tonight because of that.
"But it's about continuing to push forward. I'm going to miss some and I'm going to make some. You've always got to stay shooting."
Herro is the hero
In a Florida showdown, Tyler Herro sank a jump shot with 0.1 of a second remaining to give the Miami Heat an 89-88 NBA thriller triumph over the host Orlando Magic.
Herro scored 20 points to lead the Heat, whose president Pat Riley said hours earlier that the team has no plans to trade All-Star forward Jimmy Butler.
At Washington, the NBA-worst Wizards improved to 5-23 by beating Charlotte 113-110 as Jordan Poole scored 25 points, including the go-ahead 3-pointer for Washington with 8.1 seconds remaining.
Host Atlanta got 30 points and 15 rebounds from Jalen Johnson and 27 points and 13 assists from Trae Young in a 141-133 triumph over Chicago. Zach LaVine had 37 points in a losing cause.
The Houston Rockets, led by 30 points from Jalen Green and 27 off the bench by Cam Whitmore, beat host New Orleans 128-111.
With stars Giannis Antetokounmpo and Damian Lillard out due to illness, the Milwaukee Bucks lost at home to Brooklyn 111-105 as Cameron Johnson led the Nets with 29 points.
Zach Edey had 21 points and 16 rebounds and Jaren Jackson added 21 points and 11 rebounds to spark the Memphis Grizzlies over visiting Toronto 155-126.
