Having been largely kept in check in Monday’s game one loss to the Spurs, the league’s back-to-back Most Valuable Player scored 30 points and provided nine assists.
The Thunder’s home win tied the series at 1-1, with the teams next headed to San Antonio for games three and four on Friday and Saturday.
“The guys brought it tonight, knowing what it would have meant if we lost this one,” said Gilgeous-Alexander.
“We brought the energy from the jump.”
Two nights after it had taken a double-overtime classic to separate them, the two teams with the best NBA regular-season records put on another intense display.
Following a tied first quarter, the Thunder roared ahead for an 11-point half-time lead.
Gilgeous-Alexander, who had endured a sluggish start in the previous game, led the charge from tip-off, regularly scoring from mid-range.
His team hustled for 13 turnovers worth 16 points in the first half alone.
The Spurs’ Victor Wembanyama, having dazzled in game one with 41 points and 24 rebounds, was stifled, frequently wrestling with Isaiah Hartenstein and double-teamed by an aggressive Thunder defence.
But his teammate Stephon Castle responded in style, leaping for a sensational dunk over the head of seven-foot-tall Hartenstein that left the crowd and players gasping.
From 13 points down, the Spurs, without starting guard De’Aaron Fox for a second consecutive contest due to a right ankle sprain, rallied to pull level midway through the third.
But San Antonio never quite managed to retake the lead, with Oklahoma City soaking up the pressure.
“The guys were ready to play, (we) didn’t get discouraged by the runs they made,” said Gilgeous-Alexander after the game.
“Obviously, they’re a good team, they are gonna make runs.”
On a night of intense physicality, Oklahoma City’s Jalen Williams and San Antonio’s Dylan Harper both left the court with injuries, and did not return.
The Thunder extended their advantage again in the final quarter.
Gilgeous-Alexander sank yet another step-back jump shot before an Alex Caruso lay-up extended the lead to nine with 20 seconds remaining.
“We got a W, it’s all you can ask for. Now we got to go on the road against a really good team and go get one,” said Gilgeous-Alexander.
A downcast Wembanyama said Gilgeous-Alexander had “made shots, but nothing that he hasn’t made all season.”
“We worked on it, we just didn’t apply as much,” said the Frenchman.
Oklahoma City is trying to become the first team to repeat as champions since Golden State in 2017 and 2018.
The Thunder racked up a league-best 64 regular-season wins, and swept the Phoenix Suns and LeBron James’s Los Angeles Lakers in the first two playoff rounds.
But they lost four of five regular-season contests against the Spurs, who won 62 regular-season games to return to the playoffs for the first time since 2019.
The winner of the series will face either the New York Knicks or Cleveland Cavaliers in the NBA Finals. (AFP)