Diaw scored 24 points and Ray Felton added 20 points for the Bobcats, who won 100-95 on Friday night and moved within 2 1/2 games of idle Detroit for the eighth playoff seed in the Eastern Conference.
"We did a tremendous job in the first half," Bobcats coach Larry Brown said. "The rebounding and shooting is what kept is in it. We did a great job on the boards. Winning on the road, against a quality team, is a real good win for us."
The Sixers, who have been outrebounded by 10 in four of the last 21 games, were led by Andre Iguodala with 25 points.
"They played desperate," 76ers coach Tony DiLeo said of the Bobcats. "They did a heck of a job tonight and are trying to get into that last spot."
The Sixers made a late charge and pulled to within three with less than a minute left to play in the game. But after a miss by Charlotte's Raja Bell went out of bounds off of Philadelphia's Reggie Evans, Felton drove for a layup to give the Bobcats a 100-95 lead with 7.9 seconds left.
"We were up by  then let them back in it," Diaw said. "But we held on, and that was huge. We're a young team, with a lot of potential. We've got to learn how to make plays down the stretch. It's a matter of winning games, so tonight was a big win for us."
The Bobcats, who won for the first time in five road games, shot 51.4 percent in the first half to take a 50-33 lead into the break. Meanwhile, the Sixers struggled to find any offensive rhythm as they shot just 36 percent in the first half and were outrebounded 27-12. For the game, Charlotte held a 41-23 advantage in rebounds.
"We were fortunate," Brown said. "We got a lead and then forgot how we got it. [Felton] got real tentative, but then made a real good play at the end of the game."
The Sixers missed an opportunity to stay ahead of Miami for the fifth playoff spot in the East.
"That's the same team we expected," Iguodala said. "That's a Larry Brown team. They played hard the entire game and that's what you expect."
Sixers center Samuel Dalembert missed the morning shootaround with flulike symptoms. Dalembert was limited to 22 minutes, scoring just four points despite getting the start. ... The 10 second-quarter points scored by the Sixers were a season low for that quarter. Their lowest quarter output was eight in the fourth quarter against New Jersey on Jan. 31 at the Wachovia Center in an 85-83 loss.