BOSTON (AP) — James Harden matched his playoff career high with 45 points and hit a go-ahead, step-back 3-pointer over Al Horford with 8.7 seconds left as the Philadelphia 76ers rallied without Joel Embiid to beat the Boston Celtics 119-115 in Game 1 of their Eastern Conference semifinal. Tyrese Maxey added 26 points and Tobias Harris finished with 18 for the Sixers, who made 17 3-pointers in the absence of MVP finalist Embiid, who sat sat out with a sprained right knee. Jayson Tatum led the Celtics with 39 points and 11 rebounds. Jaylen Brown added 23 points. Boston hosts Game 2 on Wednesday night.