Ray Allen’s dramatic 3-pointer with 10 seconds left helped the Celtics hold off a furious rally as Boston trimmed the visiting Portland Trail Blazers 99-95 Wednesday night.

Boston led 96-80 with five minutes left to play but watched Portland cut the deficit to 96-95 on Brandon Roy’s short jumper with 36 seconds to play.

But Allen nailed a long 3-pointer to extend the lead to 99-95 and Boston hung on from there.

Allen finished with just nine points and had missed his first five 3-pointers before hitting the clutch bomb from the corner to lift Boston to its fifth straight win. Paul Pierce helped the Celtics build its second-half cushion with a game-high 28 points. Pierce was 9 for 11 from field while hitting 4 of 5 from 3-point range.

Wesley Matthews led Portland (8-10), which has lost five straight, with 23 points. Andre Miller added 20.

The Celtics (14-4) were sloppy early, turning the ball over seven times in the first quarter and Portland turned it into a fast 22-12 lead. Boston had cut the deficit to 26-20 at the end of the quarter and trailed 49-48 at the half.