Boston Celtics guard Jordan Crawford (27) defends as New York Knicks guard J.R. Smith (8) shoots a 3-pointer in the first half .
Carmelo Anthony scored 34 points, Sixth Man of the Year J.R. Smith added 19, and the New York Knicks opened a 2-0 lead over the Boston Celtics with an 87-71 victory on Tuesday night.
Raymond Felton added 16 points for the Knicks, who used a 27-4 run spanning halftime to blow it open and move halfway to their first series victory since the 2000 Eastern Conference semifinals. This is their first 2-0 lead since sweeping Toronto in the first round that year.
Paul Pierce scored 18 points for the Celtics, who will host Game 3 on Friday in their first home game since the Boston Marathon bombings.
They will have to be much sharper to avoid their first opening-round elimination since 2005, before they became one of the NBA's power teams again.
Kevin Garnett had 12 points and 11 rebounds, but battled foul trouble and spent too much time walking back to the bench with a raucous Madison Square Garden crowd finally experiencing playoff success again hounding him every step of the way.
Plagued by turnovers in Game 1, when they managed eight points in the decisive fourth quarter, the Celtics watched it all fall apart 12 minutes earlier this time.
Anthony followed his 36-point opener by making 8 of 13 shots in the second half to finish 11 of 24 for the game.
He said the Knicks needed to treat the game as a "must-win," aware of the difficulty of winning in Boston on Friday with the emotional boost the Celtics will get from finally being home.
They showed that mentality after halftime, outscoring Boston 32-11 in the third quarter.
Iman Shumpert drilled two 3-pointers to open the third and tie it before Pierce scored to give Boston its last lead at 50-48. The Knicks scored 18 of the next 20 points, with the Celtics getting just two free throws from Jeff Green over the next 5-plus minutes. Anthony's jumper with 4:25 remaining in the third capped the run before Garnett finally gave Boston its second basket of the quarter 10 seconds later
The Celtics missed 10 of their first 11 shots of the third while getting outscored 24-4 to open the period.
The Celtics vowed to get Garnett more involved after he shot 4 of 12 while scoring eight points in the opener. But that plan was quickly wrecked when he picked up two fouls in the first 3 minutes, 20 seconds. The Celtics shook it off and led 20-15 when Jason Terry made a 3-pointer with 1:57 left for his first basket of the series.
But the Knicks scored 11 straight to end the period. Smith, recognized before the game for the award he won Monday, kept the celebration going with five points in the final 6.8 seconds, hitting a 36-footer at the buzzer with Celtics all over him to make it 26-20.
The Celtics quickly settled down again, ripping off an 11-0 run to take a 31-27 lead on another 3-pointer by Terry. The lead later grew to eight when Pierce made a jumper, then fired a lob pass that traveled about three-quarters of the court to a streaking Green.
They led 48-39, gave up the last three points of the half — and probably never realized they gave away momentum for good with it.