Oklahoma City Thunder sealed a spot in the NBA play-offs with 16 games of the season remaining following an impressive 118-112 win over reigning champions the Boston Celtics.

Shai Gilgeous-Alexander strengthened his case for the MVP (Most Valuable Player) award by putting up 34 points, five rebounds and seven assists in 39 minutes.

The victory means the Thunder, who are 12 games clear at the top of the standings in the Western Conference, have joined the Cleveland Cavaliers from the Eastern Conference in the play-offs.

And beating 18-time champions Boston was an important “test” to overcome for the Thunder, who are looking to win the NBA title for the first time.

“It’s huge,” Gilgeous-Alexander said after the Thunder improved to 54 wins and just 12 defeats.

“Because [the Celtics have] have done what we’re trying to do, the games against them are always going to be heightened. They’re always going to be a little bit more exciting.

“There’s no better test in the NBA.”

The Celtics, who have now won 49 and lost 17 games, are second behind the Cavaliers (won 55 lost 10) and remain on course for a play-off spot.

Jayson Tatum, who scored 33 points in 41 minutes, says his side need to improve their form if they are to win back-to-back championships.

“Everybody has to play a little bit better,” said Tatum.

“Better at the margins, the little things. You’re playing against contending teams that are not really going to beat themselves.

“And the little things, not fouling jump shooters at the end of the clock, live ball turnovers, things like that, [we] just got to be a little bit better on.”