The Nets overcame a five-point deficit in the final minute of the fourth quarter to force the extra period and survived down the stretch to end a three-game losing streak.
After Lopez produced what turned out to be the final points of the game, Willie Green missed a jumper for the Hornets.
Kris Humphries grabbed the rebound for New Jersey and was fouled, but he missed both attempts from the line with 3 seconds to go to give New Orleans another chance. Chris Paul, however, missed a 3-pointer at the buzzer to leave the Hornets with their fourth straight loss and their sixth setback in seven games.
Sasha Vujacic scored 25 points for New Jersey and Lopez had 20 points to go with seven rebounds.
New Orleans was led by 32 points and 15 rebounds from David West.