Mathurin said: “The main thing is you have to be resilient. You have to be the aggressor in order to win games.”
The Pacers, who went into the game after a 123-107 defeat in game two, extended a run of not losing consecutive games since March.
Shai Gilgeous-Alexander, the NBA’s Most Valuable Player, scored 24 points for the Thunder but only three in the fourth quarter.
Jalem Williams top-scored for the visitors with 26 points, while Chet Holmgren scored 20 points and made 10 rebounds for a Thunder side that gave up 19 turnovers which led to 21 points for the Pacers.
“In the fourth quarter I just thought they really outplayed us on both ends,” said Thunder coach Mark Daigneault.
Game four will take place at the same venue at 20:30 local time on Friday (01:30 BST, Saturday).
