Shai Gilgeous-Alexander scored 35 points as the Oklahoma City Thunder launched the defense of its NBA crown with a thrilling season-opening 125-124 double-overtime victory over the Houston Rockets on Tuesday.

Gilgeous-Alexander, the reigning NBA and NBA Finals Most Valuable Player, drew a crucial foul with 2.3 seconds remaining before nailing two free throws to settle an epic duel with a new-look Rockets side spearheaded by Kevin Durant and Alperen Sengun.

Gilgeous-Alexander's winning free throws settled a triumphant occasion for the Thunder, which had earlier seen its players and staff presented with diamond-encrusted championship rings to mark last season's NBA Finals victory.

However after watching Oklahoma City hoist the franchise's first ever championship banner, the Rockets had threatened to spoil the party for long periods, with Sengun and Durant combining superbly to keep Houston in front for much of the game.

"Grit, determination and defense," Gilgeous-Alexander said when asked to sum up the Thunder's nail-biting win.

"We know that when we do it (on defense) we give ourselves a chance no matter what's going on — makes, misses, good luck or bad luck. We did enough defense tonight to get the win. We're pretty rusty, but it's a good start."

Gilgeous-Alexander was backed by 28 points from Chet Holmgren, while Ajay Mitchell caught the eye with 16 points off the bench that included a trio of three-pointers.

Turkish star Sengun led the Houston scoring with 39 points that included five three-pointers, while Durant, who joined from the Phoenix Suns in the close season, added 23 points.

The Rockets had led by 12 points in the third quarter, but Oklahoma City came roaring back to edge ahead late in the fourth quarter.

Durant put the Rockets back in front 104-102, but Gilgeous-Alexander's pull-up with three seconds remaining knotted the score once more and took it to overtime.