Shai Gilgeous-Alexander scored a career-high 55 points to lead reigning champion Oklahoma City over Indiana 141-135 in double overtime on Thursday in a historic rematch of last season's NBA Finals.

Hours after the league was rocked by a massive illegal gambling probe, reigning NBA Most Valuable Player Gilgeous-Alexander dragged the Thunder to victory.

The Canadian added eight rebounds and five assists while hitting 15-of-31 shots from the floor and 23-of-26 free throws to lead a 45-of-51 Thunder effort from the line.

The 27-year-old guard, last season's top NBA scorer, netted nine points in the second overtime to lift Oklahoma City over a determined Pacers squad.

After the Thunder won their season opener at home Tuesday over Houston 125-124 in double overtime, they became the first club in NBA history to go into double overtime in their first two games of a campaign.

Gilgeous-Alexander, whose prior career-best was 54 points, managed his fifth NBA career 50-point game.

Ajay Mitchell came off the bench to score 26 points for Oklahoma City and Aaron Wiggins added 23 points, while Isaiah Hartenstein grabbed 14 rebounds and Chet Holmgren contributed 15 points and 12 rebounds. (AFP)