Horford collected 22 points, 10 rebounds and five assists for the injury-ridden Celtics, who rallied from a 16-point halftime deficit.

Jayson Tatum contributed 17 points and Jaylen Brown 16 for Boston, which won its fourth straight game.

CJ McCollum scored 22 points and Damian Lillard had 21 points and nine assists for the Trail Blazers, who had won seven of their nine previous contests. Moe Harkless added 19 points and eight rebounds off the Portland bench.

Three of Boston's top six scorers were out due to injury -- starting point guard Kyrie Irving (quad), starting forward Marcus Morris (hip) and reserve guard Marcus Smart (hand).

Harkless scored 14 points -- hitting 4 of 4 3-point shots -- to help stake Portland to a 54-38 halftime lead. Lillard had only four points before halftime on 1-for-9 shooting, including 1-for-6 from 3-point range.

The Blazers' advantage was 57-42 when Boston went on a 18-4 run to trim the margin to 61-60 midway through the third quarter. Portland carried a 73-69 edge into the final period.

The Celtics tied it at 75-75 early in the fourth quarter. Portland kicked it back up to 85-79, but Tatum's 3-point shot squared it at 85-85 with 3:34 left.

Horford's 3 gave Boston its first lead since the game's first three minutes at 88-85 with 2:56 to go. Tatum followed with a jumper to make it 90-85 with 1:59 remaining.

McCollum's trey cut it to 90-88 with 1:36 to play. Brown followed with a 3 to make it 93-88 with 1:13 to go. Lillard answered with a 3 to get Portland within 93-91 with 1:05 remaining.

Lillard's driving basket tied it at 93-93 with 35 seconds to go. Terry Rozier's 20-footer pushed Boston back in front 95-93 with 13.6 seconds on the clock. Lillard's three-point play gave Portland a 96-95 advantage with 7.2 seconds on the clock, setting up Horford's heroics.

With Jusuf Nurkic scoring 10 early points, Portland jumped to a 21-10 lead. Boston started the game 4-for-21 from the field. The Blazers took a 26-19 advantage into the second quarter.

Portland extended its edge to 39-28 early in the second period. The Celtics cut it to 39-36, but the Blazers ended the quarter in a 12-0 run to go into intermission ahead by 16 points.

--Field Level Media