Playing near Payton's home in a Dallas suburb, Brees threw for 446 yards and three touchdowns and led a drive to Garrett Hartley's winning 20-yard field goal in overtime, and the Saints took the Cowboys' playoff fate out of their hands with a 34-31 overtime victory on Sunday.
The Cowboys (8-7) regained control of their postseason hopes when the New York Giants lost at Baltimore later Sunday. Dallas will make the playoffs as the NFC East champion with a victory at Washington next weekend. A wild-card spot is no longer a possibility for the Cowboys.
That game has been flexed to prime time by the NFL.
The Saints, who started 0-4 after being stunned by the yearlong ban for Payton in the team's bounty scandal, lost their faint playoff hopes when Minnesota beat Houston, and had to hold off a two-touchdown rally in the final 3:35 from the Cowboys.
"We're never going to let anyone tell us we're not playing for something," Brees said. "We knew there were a lot of things that had to happen. We wanted to worry about the things we could control. What would have been worse is if Minnesota had lost and we had lost."
After New Orleans forced a punt on the first possession of overtime, Brees moved the Saints to the Cowboys 33. He completed a pass to Marques Colston, who took a couple of steps before Morris Claiborne stripped the ball, sending it rolling about 20 yards to the Dallas 2.
Jimmy Graham, who said he dislocated a finger on a 26-yard catch to start the drive, won a scrum with Dallas' Eric Frampton, and the completion that started the bizarre play was held up on review, clearing the way for Hartley's kick.
"I looked at the replay and I knew there was a fumble," Claiborne said. "I was looking at it saying, 'Please, let the pass be incomplete.' "
Referee Walt Coleman confirmed the call on replay.
"He had two feet down, had possession of the ball and turned up field and got hit as his third step was coming down," Coleman said to a pool reporter. "He had possession and time enough to do something with the football -- a football move."
Cowboys owner and general manager Jerry Jones said he believed it was a catch and fumble.
Said Coleman, "He doesn't have to tuck it. So long as he has possession of it and moving it from one and to the other, he doesn't have to tuck it away. He just has to have possession of the ball to be able to do something with it, like a normal football act. But he doesn't have to tuck it against his body."
The Cowboys started the day with their playoff fate in their hands, and ended it the same way thanks to the Ravens, who beat the Giants 33-14. A Dallas win over the Redskins would guarantee a tie atop the NFC East, and the Cowboys hold the tiebreaker edge.
"When you are in this situation, you have to go forth like you are playing for a playoff spot," Dallas defensive end Marcus Spears said. "Trying to determine what will happen, all of that will get in the way of us preparing for the Redskins."
The Cowboys pulled within a touchdown on a 16-yard pass from Romo to Dwayne Harris and got the ball back with 1:29 remaining. Romo led the Cowboys 64 yards in seven plays, capped by the tying toss to Austin, who caught the ball on his knees in the end zone. It was Dallas' third overtime game in the past five at home.
"There was no panic," Brees said. "It was almost like we knew the game would come down to something like this. We just wanted that opportunity and the defense gave it to us."
Romo also had a pair of 58-yard scoring passes to Dez Bryant, who had a career-high 224 yards receiving. Romo was 26 of 43 and broke his own franchise record for passing yards in a season. He has 4,685.
The Saints, coming off a 41-0 blowout of Tampa Bay, took the lead in the third quarter after a 54-yard punt pinned Dallas at its 3. On the first play, Curtis Lofton stripped DeMarco Murray and Lofton recovered at the 5. Brees found Pierre Thomas open at the goal line for a 24-17 lead.
Brees was 37 of 53 in the ninth 400-yard game of his career.
"I don't know how many more accolades I have to say about him," Saints interim coach Joe Vitt said. "You want me to put them on my W2 form or what?"
The Cowboys put the Saints at their 2 with a 63-yard punt on their next possession, but Brees responded with a touchdown drive keyed by a 60-yard completion to Colston, who had 153 yards receiving. Colston broke a tackle by Gerald Sensabaugh before Sterling Moore ran him down at the Dallas 3.
The Saints turned a 14-7 deficit late in the first half into a 17-14 halftime lead in the final 1:11.
Brees led a 90-yard scoring drive that included Vitt changing his mind and going on fourth-and-1 from the Dallas 23. A completion to Colston was overturned on replay, but Cowboys linebacker Anthony Spencer lined up offside to give the Saints a first down anyway. Brees threw a 6-yard scoring pass to Lance Moore three plays later.
Dallas tight end Jason Witten had two catches in OT, breaking Tony Gonzalez's NFL season record of 102 catches for a tight end set in 2004. Witten has 103. ... Cowboys LB Ernie Sims left in the first half with dizziness a week after sustaining a concussion. ... Saints CB Jabari Greer, who had two interceptions last week, left the game with a concussion.
Information from ESPNDallas.com's Todd Archer and The Associated Press was used in this report.