"We were just flat," Philadelphia coach Doug Collins said. "We had zero, zero energy and we got so far behind."
Andre Iguodala returned to the Philadelphia starting lineup after missing the previous seven games with tendinitis in his right Achilles, but he was largely ineffective and didn't seem to have the same explosiveness to the basket. Iguodala shot 0 for 7 and finished with one point, seven assists and four rebounds.
It was Iguodala's lowest point total since scoring one point at Houston on Dec. 4, 2004, his rookie season.
"I thought he was rusty," Collins said.
Collison snapped a tie game with a short jumper in the lane, pushing the Pacers to a 101-99 lead. After Williams missed a 3-pointer for Philadelphia, Roy Hibbert extended the Pacers' advantage to 103-99 with an 8-foot jump hook as the shot clock expired and 1:24 was left in regulation.
"Hibbert made a big shot," O'Brien said.
The Sixers previously led 94-92 after Meeks connected on a long 3-pointer. Indiana came right back with five straight points -- a 3-pointer by Granger and a jumper by Brandon Rush -- to go ahead 97-94 with 3:28 remaining.
Holiday then tied the game again at 97 with a 3-pointer.
There were many empty areas in the lower bowl of the arena thanks to a pending snowstorm which developed right before tip-off. But the estimated crowd of about 5,000 was treated to a game that featured numerous lead changes in the fourth quarter.
Dunleavy scored 15 points in the first quarter and had 18 by halftime as the Pacers built a 57-49 advantage. Indiana shot 52 percent from the field and led by eight despite not attempting one free throw.
Collison had eight assists at halftime for the Pacers. Sixers C Spencer Hawes was whistled for a technical foul with 10:43 left in the third. Holiday added eight assists and seven rebounds.