Flynn overcame an early fumble off a blown protection to lead a methodical field-goal drive that included a pair of third-down conversions.
Pryor excelled with his legs and arm on a pair of second-quarter drives, but threw one ill-advised interception before responding with a field goal drive of his own.
Here are five takeaways from the game.
1. PRYOR'S GREED: Pryor has spent so much time on the practice field this offseason trying to prove he's more than an athletic quarterback who is a threat to run the ball.
That may have come back to bite him on his first drive of the preseason. After moving the Raiders down the field with two long runs on the read option and completing three passes to move Oakland inside the 10, Pryor made a horrible mistake.
On a third-and-4 from the 6, Pryor rolled to his right and had room to run for a first down and possible a touchdown. But instead he threw the ball across his body toward the middle of the field and rookie safety J.J. Wilcox intercepted the pass in the end zone.
"I looked at the pictures and I could have ran it easy," Pryor said. "That was just me being greedy. Maybe in the back of my mind I was saying, `Hey, I want to throw a touchdown pass. People think I can't."
2. ROMO'S NIGHT: After sitting out the Hall of Fame game after offseason surgery to remove a cyst from his back, Dallas quarterback Tony Romo played two series against the Raiders.
His first didn't go well as the Cowboys committed a holding penalty, Romo had a pass batted at the line and then was sacked on a drive that started at the Oakland 16. The Cowboys settled for a field goal.
Romo was much better on his second drive, completing three passes for 55 yards to Dez Bryant and a 11-yarder to Miles Austin before Dallas stalled at the 8 after the Cowboys had their second false start penalty of the game.
"We did what we've been doing in training camp," he said. "We've been moving the ball really well. We would have liked to have scored a touchdown but we got hurt by penalties more than anything. That's stuff that's just going to hurt you no matter what."
3. SIO'S SACK: With three projected starters on the defensive line sitting out the preseason opener, the Raiders struggled to get any pressure on the quarterback.
The one exception was rookie Sio Moore, who brought down Romo on Dallas' opening drive. Moore, a 6-foot-1, 240-pound linebacker from Connecticut spent some time lining up with his hand on the ground as an undersized defensive end. Coach Dennis Allen said that's something the Raiders might do at times throughout the season.
"It's great to me because it means the coaches want to be able to put me in positions and I want them to be able to trust me," Moore said.
4. SHODDY SPECIAL TEAMS: The biggest issue from this game for the Cowboys has to be their special teams units.
The problems started early when Dan Bailey had a 26-yard field goal attempt blocked in the second quarter. They mounted in the second half when Greg Jenkins returned a kick 51 yards following Dallas' go-ahead score. After the defense came up with a stop, rookie B.W. Webb dropped a punt from Marquette King, giving the Raiders the ball at the Cowboys 9 to set up the winning field goal.
"Those are plays that are going to hurt you," coach Jason Garrett said. "Those aren't winning football plays. We got to make sure we correct that."
5. THE BUTLER DID IT: The Raiders have few proven receivers, giving an opportunity to some young players to shine. Seventh-round pick Brice Butler stepped up in his first NFL action, with an impressive 40-yard catch-and-run followed by a diving 30-yard touchdown catch from undrafted rookie Matt McGloin in the third quarter.
"I am 23-years old and I have been waiting on that moment my whole life," Butler said.
AP NFL website: www.pro32.ap.org