James had another James-type night against one of the worst teams in the NBA. He went 12 for 26 from the floor, got hot in the fourth and silenced another road crowd that packed the place just to watch him play.
Mo Williams hit back-to-back shots in the fourth that gave the Cavaliers a lead they would never relinquish and scored 12 points.
Andre Iguodala led the Sixers with 26 points, and Thaddeus Young and Allen Iverson each had 16. The Sixers have lost 13 of 14 games. The crowd chanted "We Want A.I.!" with Iverson on the bench as the Sixers made a fourth-quarter charge that put them ahead against a team that has 13 more victories. Iguodala's 3-pointer with 5:50 left stretched the lead to 94-90.
But James came right back and sank his own 3. He then matter-of-factly hit another one that made it 96-all.
James dished to Williams for a long jumper that gave the Cavs a 98-96 lead. Iguodala, who takes all the big shots for the Sixers, missed a 3 and Williams capitalized with a 3-pointer for a 101-96 lead.
The 3s were the first two field goals of the game for Williams, who was averaging 16.7 points.
James stepped back for an 18-footer that all but sealed the win for the Cavaliers. They were coming off a 99-89 win over New Jersey on Tuesday night.
Iverson, Iguodala and Young brought the Sixers back from an early 12-point hole to take the lead in the third quarter. Iverson put them up for the first time on a 19-footer from the wing that made it 68-67. He had an assist on one of Philadelphia's more dazzling plays of the season - a running alley-oop pass from beyond the 3-point arc to a soaring Iguodala for the dunk and a 74-72 lead.
Daniel Gibson quickly quieted, and seated, the roaring crowd of 19,517 with a 3-pointer for the lead. The Cavaliers led 83-80 at the end of the third.
Halladay, acquired Wednesday from Toronto, had earned the loudest ovation before the A.I.-A.I. alley-oop. He received a standing ovation when he was introduced, and smiled and waved to the fans from his suite.
Sixers forward Marreese Speights played for the first time since he tore the MCL in his left knee on Nov. 14. Speights showed no sign of injury when he leaped off the court for a one-handed dunk in the fourth that cut the hole to 87-84.
Sixers forward Elton Brand was benched for the second straight game, and might be permanently there. Coach Eddie Jordan wants the smaller, quicker backcourt of Iverson and Holiday, and Young, Dalembert and swingman Iguodala on the court.
Iguodala hurt his ribs in Monday's win, but looked sharp against the Cavs.
Brand has not complained about his role, though he feels he should be a starter. His three-point play in the middle of the fourth tied the game at 89.
Jordan used Brand at center in the fourth quarter. Brand still played 33 minutes and had 14 points.
He just didn't sign a five-year deal in 2008 to ride the bench for a lousy team.
NOTES: James' appearance brought out several local sports stars, including Phillies slugger Ryan Howard, Flyers goalie Ray Emery and forward Mike Richards, and Eagles wide receiver DeSean Jackson. ... The 76ers have used six different lineups this season after using six different total last season when they reached the playoffs. ... Cavs G Delonte West scored four points in 23 minutes after he was inactive Tuesday night.