Romo threw an 8-yard touchdown pass to favorite target Jason Witten to cap a brief but successful night before the Raiders rallied for the victory.
Romo completed his four passes on the night to four receivers before leaving with a 7-3 lead.
Oakland's Bruce Gradkowski engineered three touchdown drives against mostly backups on the Cowboys defense -- throwing a 3-yard touchdown pass to Tony Stewart in the second quarter.
Romo played just two drives, going three-and-out on the first after former teammate Greg Ellis batted down his first pass of the game, and throwing the TD to Witten on the second.
Roy Williams, who struggled after coming over from Detroit during last season, caught one pass from Romo for 12 yards. Romo also completed passes to Martellus Bennett and Felix Jones on the drive.
Sam Hurd had five catches for 79 yards from Jon Kitna.
The Cowboys wasted a scoring opportunity at the end of the half when Kitna botched a shotgun snap at the 2 from Cory Procter, leading to a 16-yard loss. Nick Folk missed a 36-yard field goal.
-- Ellis, who spent 11 seasons with Dallas before being released in June, visited with Cowboys owner Jerry Jones and some of his former teammates before the game.
-- Injured cornerbacks Terence Newman (groin), Mike Jenkins (ankle) and rookie Michael Hawkins (knee) missed the game for Dallas. Orlando Scandrick and Alan Ball got the starts.