The Cleveland Cavaliers collapsed as the Atlanta Hawks completed a remarkable comeback in overtime, while Russell Westbrook made history in the NBA.

Reigning NBA champions the Cavaliers squandered a 26-point lead as they lost 126-125 on Sunday.

The Hawks outscored the Cavs 44-18 in the fourth period to force OT, where Atlanta triumphed as Cleveland dropped into a tie with the Boston Celtics for top spot in the Eastern Conference.

Westbrook broke the record for most triple-doubles in a regular season with his 42nd in the Oklahoma City Thunder's 106-105 victory against the Denver Nuggets.

The six-time All-Star also nailed the buzzer-beating shot to lift the Thunder to victory.

James Harden had a triple-double of his own as the Houston Rockets topped the Sacramento Kings 135-128.

LEBRON, IRVING CAN'T STOP WORRYING FORM

LeBron James and Kyrie Irving put up big games for the Cavaliers but it was not enough.

James had a triple-double with 32 points, 16 rebounds and 10 assists, while Irving scored 45 points as the Cavs lost back-to-back games.

The Cavs are now in a tie alongside the Celtics atop the east with two regular-season games remaining.

WESTBROOK ECLIPSES ROBERTSON

A 55-year record was broken on Sunday as Westbrook passed Oscar Robertson's triple-double feat.

With his 50 points, 16 rebounds and 10 assists, Westbrook made history.

Already averaging a triple-double this regular season, the 28-year-old brought up his 79th career triple-double.

HARDEN JOINS IN THE FUN

The MVP candidate had 35 points, 15 assists and 11 rebounds for his 21st triple-double of the season.

It was the first time the Rockets had swept the Kings in four games since 1997-98.

RAPTORS, PISTONS WIN

DeMar DeRozan scored 35 points to lead the Toronto Raptors past the New York Knicks 110-97, while the Detroit Pistons were too good for the Memphis Grizzlies 103-90.

The Los Angeles Lakers edged the Minnesota Timberwolves 110-109 and the Phoenix Suns trumped the Dallas Mavericks 124-111.

DURANT BACK IN ACTION

After returning on Saturday, Kevin Durant will take to the court again when the Golden State Warriors host the Utah Jazz on Monday. The San Antonio Spurs are at the Portland Trail Blazers, the Cavaliers face the Miami Heat and the Celtics welcome the Brooklyn Nets.