Oklahoma City's Russell Westbrook broke Oscar Robertson's 56-year-old NBA record with his 42nd triple-double of the season, and broke Denver's hearts with a buzzer-beating three-pointer for a 106-105 victory.
That shot eliminated the Nuggets from playoff contention.
Westbrook had 50 points, 15 rebounds and 10 assists, including the Thunder's final 13 points.
Danilo Gallinari scored 22 of his season-high 34 points in the third quarter to lead the Nuggets.
Paul Millsap scored 22 points and Atlanta took advantage of Cleveland's fourth-quarter collapse to overcome a 26-point deficit and stun the Cavaliers 126-125 in overtime
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Kyrie Irving scored 45 points for Cleveland, and LeBron James had a triple-double with 32 points, 16 rebounds and 10 assists before the four-time MVP fouled out.
Tim Hardaway Jr. added 21 points to help the Hawks beat Cleveland for the second time in three days.
The defending champion Cavaliers and Boston Celtics are tied at the top of the Eastern Conference with two regular-season games remaining - but the Cavs hold the tiebreaker, should they finish level, after winning the season series.
DeMar DeRozan scored 35 points as Toronto beat New York 110-97 to wrap up at least the No. 3 seed in the Eastern Conference.
The Raptors reached 50 victories for the second straight season and can still finish second if they beat Cleveland in their regular-season finale and Boston lose their final two.
Kyle Lowry added 17 points and 11 assists for Toronto. New York rookie Willy Hernangomez tied his career high with 24 points and 11 rebounds.
James Harden recorded his 21st triple-double of the season to lead Houston to a 135-128 win at Sacramento.
Harden had 35 points, 11 rebounds and 15 assists for the Western Conference third seed Rockets against the Kings.
D'Angelo Russell's three-pointer on the buzzer lifted the Los Angeles Lakers to a 110-109 victory over Minnesota, despite Karl-Anthony Towns' 40 points and 21 rebounds for the Timberwolves.
Reggie Bullock and Boban Marjanovic scored 14 points each as the Detroit Pistons beat the Memphis Grizzlies 103-90, while Devin Brooker and TJ Warren scored 21 each as the Phoenix Suns enjoyed a 124-111 win over the Dallas Mavericks.
