Shai Gilgeous-Alexander equalled Wilt Chamberlain's 63-year-old 20-point scoring record on Monday as the Oklahoma City Thunder defeated the Denver Nuggets 129-126 in a pulsating clash of the Western Conference titans.

Gilgeous-Alexander finished with 35 points, 15 assists and nine rebounds to pull level with Chamberlain's longstanding mark of scoring 20 points or more in 126 consecutive games set between 1961 and 1963.

But Gilgeous-Alexander's equalling of Chamberlain's streak was almost a footnote to a spellbinding individual performance that saw the reigning NBA Most Valuable Player seal victory with a game-winning three-pointer with three seconds on the clock.

Gilgeous-Alexander had given the Thunder what looked like a winning 126-122 lead with 14 seconds on the clock after another superb three-pointer.

The Nuggets though came roaring back with a nerveless three-pointer from Nikola Jokic, and a foul from Jaylin Williams in the same play allowed Jamal Murray to level it for Denver from the free-throw line.

With overtime looming there was one last throw of the dice for Oklahoma City, and Gilgeous-Alexander duly delivered, launching a 25-foot step back three to snatch victory at the death.

"I just tried to make a play I was comfortable making," Gilgeous-Alexander said after sending the Oklahoma City home crowd into raptures. 

"I tried to create space to get a shot off – it went down."

Gilgeous-Alexander's winning three was the final act of the latest in a series of blockbuster duels between the two Western Conference heavyweights, who came to blows when the two teams met last month.

Gilgeous-Alexander said the Nuggets had forced the Thunder to raise their game.

"They're a really good opponent. They've won championships, they have really good talent, really good coaching and really good schemes," Gilgeous-Alexander said. 

"Playing against them brings out the best in of you. That's the level of basketball that you want to play at the end of the season."

Gilgeous-Alexander received plenty of scoring support with Williams finishing with 29 points -- 21 of them from outside the arc == and Ajay Mitchell adding 24 off the bench.

Jared McCain and Isaiah Joe had 13 points apiece.

Denver were led by a Jokic triple double. The Serbian star finished with 32 points, 14 rebounds and 13 assists, while Tim Hardaway Jr. erupted with 28 points off the bench including eight three-pointers.

Oklahoma City's victory extended their winning streak to six games and leaves them three wins clear of San Antonio at the top of the Western Conference with a 51-15 record.

Denver slipped to 39-26 and are now sixth, occupying the last automatic playoff berth in the West.

James Harden led the Cleveland Cavaliers scoring with 21 points in a 115-101 defeat of his former club the Philadelphia 76ers.

The struggling Utah Jazz defeated the Golden State Warriors 119-116 in Salt Lake City while the Brooklyn Nets thumped the Memphis Grizzlies 126-115.