The Miami Heat caused an upset against the top-seeded Boston Celtics to level their Eastern Conference NBA play-off duel, last night.

Underdogs Miami, who suffered a 20-point thrashing in the first game of the series, recovered to earn a 111-101 road victory.

The Heat torched the Celtics with 23 three-pointers – two shy of the NBA play-off record.

Tyler Herro sank six three-pointers and added 14 assists, with all five Heat starters posting double-digit points.

Miami are without star wing Jimmy Butler and starter Terry Rozier through injury and, after Sunday’s 114-94 defeat, many thought the Celtics would wrap up a four-game sweep.

Herro says they are not deterred by their underdog tag.

Tyler Herro.

The best-of-seven series moves to Miami for the third game on Saturday.

Elsewhere on Thursday, the Oklahoma City Thunder claimed a commanding 2-nil lead in their Western Conference play-off series against the New Orleans Pelicans.

The Thunder cruised to an emphatic 124-92 victory.

Game three is on Saturday in New Orleans.