Diaw, who finished with 16 points and eight rebounds, drove the lane for a basket with 3:01 to play after the Nets' Devin Harris hit a layup to cut the Charlotte lead to 83-81.
After Diaw's basket, the Nets had five shots on their next possession but they could not get one to fall.
Vince Carter had 19 points to lead the Nets, while Lopez and Harris added 14 apiece.
The win was only the third (3-9) on the road this season for the Bobcats, who have started putting things together after acquiring Diaw and Raja Bell in a deal with Phoenix.
New Jersey is now 5-11 at the Izod Center this season.
The Bobcats, who constantly found the open man underneath with pick and rolls, seemed to take command with a 31-11 spurt that bridged about the final nine minutes of the first half and the opening minutes of the third quarter.
A shot in the lane by Diaw gave them a 54-41 lead early in the third quarter and a free throw by Felton later pushed the margin to 67-52 with 2:55 left in the period.
Bobby Simmons, who missed the last two games while awaiting the birth of his daughter, came off the bench and hit a 3-pointer to spark a 23-11 spurt that got the Nets to within 78-75 on a dunk by Keyon Dooling with 6:50 left in the game.
Two free throws by Okafor, who had nine rebounds, and a 3-pointer by Wallace pushed the lead back to 83-75.
Harris scored six straight points to close the gap to two points but that was as close as New Jersey would get.
NOTES: Trenton Hassell started his fourth straight game at small forward for Simmons, who also missed a game with a bruised shoulder. ...The Bobcats are 9-3 when leading after three quarters. ... Bell is 9-for-9 from 3-point range in two games at the Izod Center this season. He was 6-for-6 playing for the Suns in a 114-86 win early this season and he hit all three of his long-range tries on Friday night.
