The Denver Nuggets completed a stunning comeback from a 3-1 series deficit against the Utah Jazz as they moved through to the second round of the NBA playoffs.

Denver booked their spot in the Western Conference semi-finals thanks to Tuesday's tense 80-78 victory, which was sealed by Nikola Jokic's tie-breaking basket with 27 seconds remaining.

The Nuggets faced elimination after losing three of the opening four games against the Donovan Mitchell-inspired Jazz at Walt Disney World Resort, but Jamal Murray's heroics helped Denver stay alive in the postseason.

Murray's 50 points on Sunday forced a deciding Game 7 in the opening round in Orlando, Florida.

In the do-or-die showdown, Jokic proved to be the difference in the closing stages as Jazz guard Mike Conley's three-pointer spun out at the buzzer in a dramatic finish.

Jokic posted 30 points and 14 rebounds for the third-seeded Nuggets, who became the 12th team in NBA history to overcome a 3-1 deficit to win a series, despite blowing a 19-point lead on Tuesday.

Murray had 17 points of his own as the Nuggets await second seeds the Los Angeles Clippers in the second round.

The Jazz were led by Mitchell's 22 points and Rudy Gobert's double-double of 19 points and 18 rebounds.

Meanwhile, the Boston Celtics topped defending champions the Toronto Raptors 102-99 for a commanding 2-0 lead in the Eastern Conference semi-finals.

Jayson Tatum scored 34 points and Marcus Smart put up 16 points in a devastating stretch early in the fourth quarter as the Celtics claimed Game 2.

Smart (19 points) made five three-pointers in a three-minute span to help the Celtics move closer to the Conference Finals.

OG Anunoby's 20 points led the Raptors, who also had 19 from Fred VanVleet.

Thunder face Rockets

It will be winner-takes-all on Wednesday when the Oklahoma City Thunder and Houston Rockets clash in Game 7 of their Western Conference first-round matchup. The Miami Heat and Milwaukee Bucks will also go head-to-head in Game 2 of their Eastern Conference semi-final.