National Basketball Association conference leaders Boston and Denver were pushed to the limit on Thursday with the Celtics escaping with a 142-138 overtime triumph over Indiana and the Nuggets edging the Cavaliers in Cleveland.

Boston star Jayson Tatum, coming off a record-setting 55-point performance in the All-Star Game, scored 31 points, including the Celtics' last four in overtime.

Denver, meanwhile, held off the tenacious Cavaliers, 115-109, while the Philadelphia 76ers erased a 17-point deficit to beat the Memphis Grizzlies, 110-105.

Tatum got off to a slow start as NBA action resumed after the All-Star break, but finished with a double-double that included 12 rebounds.

Jaylen Brown added 30 points for the Celtics, who improved their league-leading record to 43-17, but are just one game ahead of the surging Milwaukee Bucks atop the East.

The Pacers, led by 40 points and 10 rebounds from Myles Turner, erased a 10-point halftime deficit.

It was tied at 125-125 with 1:41 left in regulation.

Both Tatum and Brown coughed up turnovers from there, but Indiana's Tyrese Haliburton missed a jump shot in the waning seconds as they went to overtime.

It was knotted at 138-138 with 56.2 seconds left in the extra session, but Tatum drained two free throws and sealed the win with a tip-in with 10.4 seconds remaining.

Brown said the victory bodes well for the Celtics' stretch run to the playoffs.