Allen hit eight three-pointers - four in a first quarter that effectively put the game away - as the reeling Boston Celtics beat the Raptors 94-88 at a sold-out Air Canada Centre to bring to an end Toronto's three-game home winning streak.

And with the two teams hooking up again tonight in Boston, it'll be time for the Raptors to come up with some kind of adjustment because if they don't, Allen will continue to kill them from a distance.

"We let him get going early," Toronto coach Jay Triano said of Allen. "I thought we over-helped early and gave him a couple of looks. When a guy like that gets confidence - and he had it going - he's going to shoot the ball well.

"We made some adjustments after the first couple but by that point the damage was already done because he had his confidence, he was rolling."

And he rolled the Celtics right into a lead that grew as big as 20 points in the third quarter, a deficit Toronto had no chance to overcome. The Raptors did put on a rather stirring fourth-quarter comeback, narrowing the deficit to five with 90 seconds left, but they got no closer.

It was a nice rally built on some new-found energy but it might have had as much to do with it being easier to play down 20 than in a tight game and harder for a team that owns a 20-point lead to maintain its intensity.

Allen, who finished with a season-high 36 points, got his open looks not just because the Raptors couldn't guard him but because they couldn't guard anyone.

"I just played within what we were doing and we were moving the ball," said Allen. "The penetration always allows the ball to go to the open man ... and I got a lot of easy looks."

Triano's reference to "over-helping" means the Raptors allowed the Celtics to get open passing lanes along the baseline and that made it easy for Allen to stand on the weak side and gladly accept easy shots.

"We can't give up that baseline penetration too much; (a penetrating guard or small forward) has to see bodies and we have to discourage that pass," said Chris Bosh. "He's open but (the guard) is going to have to go through a big guy and another big guy and he's going to have to make a perfect pass and there were a couple of times where we didn't make him make a perfect pass. It was too easy."

It was going to be a long night of breaking down videotape and an early morning of teaching adjustments for the Raptors, who were once again without Jermaine O'Neal (knee) and got only 21 minutes out of Jose Calderon, who wasn't close to 100 per cent and is not with the team in Boston.

"It's a little easier to make adjustments because you saw him last night and you can kind of tweak a couple of things," said Bosh of the rare back-to-back series. "It's like practising almost - you know what plays they're going to run and you know what they're going to come at you with. We can probably fix those baseline drives and that penetration."

What Toronto also has to fix is an offence that became stagnant in the face of Boston's aggressive, pass-denying defence. Bosh and Andrea Bargnani, who had been carrying the team, were a combined 10-for-30 from the field.

"This one won't feel so bad for so long," said Triano. "You get a chance to bounce back."