Toronto Raptors guard Norman Powell (left) in the game against the Brooklyn Nets Photo: IC

Toronto reserve Norman Powell scored 12 of his 24 points in the fourth quarter as the defending champions Raptors rallied to beat Brooklyn 104-99 Wednesday in their NBA playoff series.

The Raptors took a commanding 2-0 lead in the best-of-seven Eastern Conference first-round clash, being played in the league's quarantine bubble in Orlando.

The Raptors, who had converted 22 three-pointers in a Game 1 blowout of the Nets, connected on just 25.7 percent of their three-point attempts - and 43.7 percent of shots overall - under heavy defensive pressure from a Nets team eager to even the series.

But turnovers proved crucial, with nine Toronto giveaways leading to six Nets points while 17 Brooklyn turnovers resulted in 23 points for the Raptors.

Brooklyn, trailing by three with 15 seconds remaining, had a chance to force overtime but an ill-timed pass on their final possession led to a final, decisive turnover - forced by Toronto guard Kyle Lowry - that sealed the win for the Raptors.

"We've been here before," said Toronto's Fred VanVleet, who delivered a double-double of 24 points and 10 assists. "You've just got to stick with it, weather the storm."

Trailing 80-74 through three quarters, the Raptors opened the fourth on a 17-5 scoring run, taking their first lead since the second period on O.G. Anunoby's dunk with nine minutes to play.

Powell extended the lead to eight points with a driving dunk, and the Raptors held on.

Lowry finished with 21 points and nine rebounds and Pascal Siakam added 19 points for the Raptors, who will try to take a 3-0 lead on Friday.

The Nets' hopes of battling back could be hindered by the departure from Orlando of Joe Harris, who scored 14 points with 15 rebounds before leaving the campus for what the team called a "personal matter."

Quarantine rules mean Harris will miss at least games three and four of the series.

The Boston Celtics also seized a 2-0 lead in their Eastern Conference clash with Philadelphia, shrugging off the absence of injured Gordon Hayward to thrash the 76ers 128-101.

Jayson Tatum was the star for Boston, scoring 33 points in a dominant victory.

Joel Embiid led the 76ers with 34 points and 10 rebounds.

In Western Conference action, Donovan Mitchell, scored 30 points and handed out eight assists for the Utah Jazz, who cruised to a 124-105 victory over the Denver Nuggets that knotted their series at one game apiece.

It was a sweet reversal for Mitchell, who scored 57 points in a Game 1 overtime loss.