Garrett Hartley kicked a 20-yard field goal 4:27 into overtime as visiting New Orleans ended Dallas' three-game winning streak and delivered a blow to its playoff hopes.
After the Saints (7-8) stopped the Cowboys on the opening possession of overtime, Marques Colston caught a nine-yard pass from Drew Brees before fumbling. Jimmy Graham recovered the ball at the Dallas 2, and Hartley booted his second field goal of the game on the next play to end the contest.
Tony Romo completed 26 of 43 passes for 416 yards and four touchdowns, including a pair of 58-yarders to Dez Bryant in the second quarter. Bryant, who has at least one TD reception in each of his last seven games, had nine catches for 224 yards as Dallas (8-7) fell one game behind Washington in the NFC East and play the Redskins in the final regular-season contest next week.
Brees was 37-of-53 for 446 yards and three scores while Colston had 10 catches for 153 yards. Darren Sproles also eclipsed the century mark in receiving yards, gaining 104 on seven receptions.
Dallas fell behind by 14 when David Thomas caught a 3-yard touchdown pass from Brees early in the fourth. But Romo provided late heroics to force overtime, connecting with Dwayne Harris on a 16-yard TD strike with 3:35 remaining before hitting Miles Austin for a 19-yard score on 4th-and-10 with 15 seconds to play.
GAME NOTEBOOK: New Orleans CB Jabari Greer exited the game with a concussion and did not return. It's unknown when he suffered the injury. ... Cowboys LB Ernie Sims left the contest in the first half with dizziness. Sims was forced out of last week's victory over Pittsburgh with a concussion. ... Dallas' Jason Witten set the single-season record for receptions by a tight end early in overtime with sixth catch of the day. With 103 catches, Witten eclipsed the previous mark set in 2004 by Tony Gonzalez.