BOSTON – Rajon Rondo has made dozens of last-second dashes to the basket. This time he went in the other direction.

Rondo ran into the backcourt, grabbing the inbounds pass in stride, avoiding a foul and dribbling out the final 3.4 seconds Saturday night to clinch Boston’s 92-91 victory against the Philadelphia 76ers in the opener of their Eastern Conference semifinal series.

“I feel like I could out-quick him. That’s what I did,” Rondo said. “We knew they had a foul to give. I told (Coach) Doc (Rivers) to get me the ball and I could use my speed.”

Rondo had 17 assists, 13 points and 12 rebounds for his eighth career playoff triple-double. He had six points, five assists and four rebounds in the fourth quarter, when the Celtics went on a 23-7 run to turn a double-digit deficit into a six-point lead with 1:18 to play.

“He’s an amazing player. He really is,” Sixers Coach Doug Collins said. “He takes that ball wherever he wants on the floor.”

Kevin Garnett scored 29 points — his most in the regular- or postseason this year — and added 11 rebounds to help Boston maintain home-court advantage in the best-of-seven second-round series. Game 2 will be Monday night in Boston before the series shifts to Philadelphia for games 3 and 4.

“If you’ve watched us all season, we’re not going to drop our heads,” Collins said. “We live to come back and fight just as hard in Game 2, at least as long as I’m the coach.”

Andre Iguodala scored 19 points, and Evan Turner had 16 with 10 rebounds for Philadelphia, which is in the second round for the first time since 2003. But Turner couldn’t catch Rondo in the final seconds when Philadelphia had a foul to give.

“Rondo just leaps out. That’s the last thing on your mind, him going into our side of the court,” Iguodala said. “You could have a turnover down there. It’s a gamble but it’s a good play. We could have done a better job scoping it out.”

The Sixers led 77-67 with 11 minutes to play before Boston scored 23 of the next 30 points, with Rondo making a jumper to cut it to 80-79, then another two minutes later to give Boston an 83-82 lead with 3:47 to play.

After Spencer Hawes’ basket from the right baseline put the Sixers up 84-83, Rondo drove to the basket and with his path blocked, turned and handed the ball to Garnett. He banked one in and drew a foul to give Boston a two-point lead, then added another jumper.

After misses by Turner and Lou Williams, Paul Pierce hit a fall-away jumper with 1:18 left to make it a six-point lead, the Celtics’ biggest of the night.

Boston still led by five when Jrue Holiday made a jumper, then Rondo fouled him with 3.4 seconds left and he made both foul shots. Boston inbounded the ball from between the benches, and Rondo sprinted back into the backcourt and outran Turner to the wrong basket as time expired.

Pierce, who had a sprained MCL in his left knee, scored 14 points on 3-for-11 shooting. Rondo was only 6 of 15 from the floor, but he was 3 of 6 in the fourth quarter, adding five rebounds and four assists.

Hawes scored 13 of his 15 points in the second half.

The Sixers scored the first seven points and led by 10 at the end of the first quarter, when Boston shot 30 percent. It was 45-32 when Boston scored 10 of the last 12 points in the half.

A little more than two minutes into the third, Avery Bradley outraced Rondo to a long rebound and took it in, splitting Iguodala and Holiday for the reverse layup that made it 48-47 — Boston’s first lead. Philadelphia quickly retook the lead and extended it to eight points.