June 22 (Reuters) - The Oklahoma City Thunder capped an extraordinary season by defeating the Indiana Pacers 103-91 in Game 7 of the NBA Finals on Sunday to win the franchise's first title since relocating from Seattle in 2008.

League MVP Shai Gilgeous-Alexander led the scoring in front of a raucous home crowd at Oklahoma City's Paycom Center with 29 points and 12 assists.

He was also crowned the best player of the Finals, marking the first time since Shaquille O'Neal in 2002 that the same player had won the scoring title, regular season and Finals MVP honors.

The Pacers suffered a huge blow early on when they lost star point guard Tyrese Haliburton midway through the first quarter with an Achilles injury and saw their title hopes dashed by a stifling Oklahoma City defense in the second half.

"It doesn't feel real," Gilgeous-Alexander said. "So many hours, so many moments, so many emotions, so many nights of disbelief, so many nights of belief.

"This group works hard. This group put in the hours and we deserve this," he added.

The championship capped an

extraordinary run

for the Thunder, who ended the regular season with a 68-14 record, good for the fifth-most wins in a single NBA season.

The Finals between two small-market teams was light on star power but delivered on thrills, as the surprise Eastern Conference champions Pacers pushed the best team in the league to the winner-take-all finale.

The Pacers got off on the right track as Haliburton drained his third three-pointer five minutes into the game but the night took a terrible turn for Indiana when he slipped and fell two minutes later.

The two-time All Star was in tears as his team's medical staff rushed to his side and a hush fell over the building packed with Oklahoma City fans.

Haliburton was helped to the locker room but did not return, and while there was no official update from the team a TV broadcast reported he had suffered an Achilles injury.

The resilient Pacers kept the game tight through a physical second quarter, putting up a terrific defensive effort to end the half up by one.

However, the Thunder took soon control with Gilgeous-Alexander, who went 0-5 behind the arc in the first half, lighting the fuse with a 25-foot three-point jumpshot four minutes into the third quarter.

The Pacers were masters of the late comeback in the postseason but without Haliburton they were unable to claw back the deficit with the Thunder opening the fourth quarter with a 9-0 run.

(Reporting by Amy Tennery in chauffeur services new york York; Editing by Peter Rutherford)