PHILADELPHIA (AP) — James Harden hit the go-ahead 3-pointer with 18 seconds left in overtime and scored 42 points to help the Philadelphia 76ers stave off a wild Boston Celtics comeback in a 116-115 victory on Sunday that evened their playoff series at 2-2. Marcus Smart’s potential winner was a tick too late and the Celtics now head home for Tuesday’s Game 5. Joel Embiid had 34 points and 13 rebounds. Harden added nine assists and eight rebounds. Jayson Tatum struggled to score early but finished with 24 points, 18 rebounds, six assists and four blocks.