"He played like an MVP tonight," Thunder coach Scott Brooks said of Durant, the two-time scoring champ, who also had eight rebounds, four steals and three assists.
OKC's eight-game home winning streak nearly was halted by the streaking Nuggets, who frequently blew past lagging Thunder defenders all night long.
Denver outscored the Thunder 72-46 in the paint and somehow still lost. The Nuggets also outscored OKC in fast-break points (18-17) and second-chance points (25-22).
With 7 seconds left in regulation, Durant took an inbound pass on the left wing and barreled in unimpeded for a two-hand dunk with 4.4 seconds remaining to tie the score at 111. Lawson's pump-fake, lean-in 15-footer at the final buzzer was off the mark to the right and forced overtime.
Durant had 15 points in the fourth quarter alone to go along with 12 in the first, eight in the second and 10 in the third.
Westbrook had a 14-point third quarter to help the Thunder momentarily take control after trailing by as many 14 in the second quarter.
Durant shot 19 for 28 from the field, 5 for 6 from 3-point range and 8 for 10 from the free-throw line, Westbrook went 16 for 29 from the field, 3 for 6 from 3-point range, 5 for 5 from the line and handed out nine assists, one shy of a double-double.
Ibaka was 6 for 7 from the field and the rest of the Thunder roster combined to shoot 5 for 30.
OKC guard James Harden misfired with 2 for 12 shooting from the field and was still ecstatic at what transpired.
"Unbelievable," Harden said. "It was probably the best regular-season game I have played in since I've been here. Kevin had 50, Russell had 40 and Serge a triple-double. What else can you say? It doesn't get any better than that."
Brooks sheepishly said during his opening remarks: "As you know, this is probably an understatement, that was a heck of a game."
Sunday's box score: Thunder 124, Nuggets 108 (OT)