ARLINGTON, Texas — The Dallas Cowboys dodged one bullet Monday night but couldn’t get out of the way of a second in a 20-17 overtime loss to the Washington Redskins.

Quarterback Tony Romo left in the third quarter with an injury to his surgically repaired back, though he returned in the fourth quarter after receiving an injection.

Romo expects to be back in the lineup Sunday when the Cowboys (6-2) play host to the Arizona Cardinals.

“It’s sore,” Romo said. “We’ll look it at tomorrow and get ready for next week.”

As for the Redskins (3-5), they might have found new life, recording back-to-back wins for the first time since 2012. Washington quarterback Colt McCoy, a third-stringer coming into the season, started for the first time in nearly three years and engineered the upset.

“I made a ton of mistakes early in the game,” McCoy said. “I was just a little rusty and didn’t do some things quite as well as I should have, but I settled in because our defense created turnovers and kept us in the game.

“Huge win for us.”

McCoy did more than just keep the seat warm as the Redskins await the return of starter Robert Griffin III. He passed for 299 yards, and his 16-yard pass to tight end Jordan Reed set up the game-winning field goal in overtime.

McCoy (25 of 30, one interception) was rolling to his left when he deftly dropped a floater into Reed’s hands down the sideline. Kicker Kai Forbath drilled a 40-yarder four plays later.

McCoy didn’t bite when asked about a budding quarterback controversy with Griffin recovering from a dislocated ankle.

“I prepare as if I’m the starter, whether I’m playing or not,” said McCoy, who rallied Washington past the Tennessee Titans last week. “That decision is not my decision. I’m a team player, and I’m going to do whatever they ask me to do.”

Running back Alfred Morris rushed for 73 yards and a touchdown as Washington won for the first time on the road this season in four tries. Wide receiver DeSean Jackson caught six passes for 136 yards.

“We can’t afford to lose any more games,” Jackson said.

Cowboys backup quarterback Brandon Weeden led two scoring drives in Romo’s absence. Romo completed one of passes for a loss of 1 yard in overtime, and his incompletion on fourth-and-3 ended the game.

Dallas saw its six-game winning streak end. The NFC East leaders were looking for the franchise’s first 7-1 start since 2007.

Romo was hurt while being sacked by linebacker Keenan Robinson. Romo remained on the field for several minutes while being attended to by the Cowboys’ medical staff. He eventually walked gingerly to the sideline accompanied by coach Jason Garrett.

“He got hit in the back,” Garrett said. “It appears to be a back contusion. The X-rays were negative, which is a positive for us.”

Cowboys running back DeMarco Murray extended his NFL record with his eighth consecutive 100-yard rushing game to open the season. The NFL’s rushing leader ran for 141 yards on 19 carries, putting him over 1,000 yards on the season. He also lost a fumble in the first half.

Romo finished 17 of 28 for 209 yards and a touchdown. Weeden completed four of six passes for 69 yards and a score. Murray led the Cowboys with 80 receiving yards on four catches.

On Dallas’ first possession after Romo was hurt, Murray broke off a 51-yard run on Weeden’s first play. The run set up kicker Dan Bailey’s 21-yard field goal to tie it 10-10.

McCoy answered with his best series of the night to put the visitors ahead 17-10. A 45-yard pass to Jackson set Washington up at the Dallas 8. McCoy ran the final 7 yards on a third down less than two minutes into the fourth quarter.

Weeden responded by engineering a long touchdown drive that included a 23-yard screen to Murray and ended with a 25-yard pass to tight end Jason Witten with 9:27 play.

Morris put the Redskins back on top in the third with his 5-yard touchdown run. Washington received the opening kickoff of the second half and marched 80 yards in eight plays to grab a 10-7 lead.

Dallas took a 7-3 lead into locker room despite an inconsistent first half. The Cowboys punted or turned the ball over on each of their first four drives.

What the Redskins said:

“It felt great. We haven’t won in primetime in a while. We needed that, not only for our team, but for our fans, too. They deserved that win. Hats off to us. We played a great game.” — Linebacker Ryan Kerrigan.

What the Cowboys said:

“You have to do the things that winning teams do.” — Coach Jason Garrett.

What we learned about the Redskins:

1. Washington can’t be counted out of the playoff race. A two-game winning streak, including a road win over the division’s first-place team, should instill the confidence needed for a second-half run. Wins over a pair of teams with losing records (the Minnesota Viking and Tampa Bay Buccaneers) the next two games would get Washington to .500 with six games to play.

2. The quarterback position isn’t as dire as once though. Colt McCoy came off the bench to pick up two wins, and Robert Griffin III is healing on the sideline. The Redskins can afford to be conservative awaiting RG3’s return as long as McCoy turns in the kind of steady performance he enjoyed Monday.

–QB Colt McCoy completed 25 of 30 passes for 299 yards and ran for his first touchdown since 2010. He went 5-for-5 for 49 yards in overtime, leading to the game-winning field goal. According to the Elias Sports Bureau, McCoy’s 83.3 percent completion rate was the best in a single game by a Washington quarterback with at least 30 passes.

–WR DeSean Jackson caught six passes for 136 yards, with a long of 49 yards. He has a league-high seven catches of at least 40 yards this season. It was his fourth 100-yard game of the season and his third in the past four games.

–S Brandon Meriweather made his presence felt all over the field, forcing a fumble and also coming up with a fumble recovery. He was credited with seven tackles, including two sacks.

What we learned about the Cowboys:

1. The margin of error is slim if Dallas turns the ball over and fails to convert on third down. The Cowboys lost two fumbles, both in the first half, and finished 5-for-12 in third-down efficiency.

2. The defense didn’t do enough after halftime to win. After being the league’s worst defense last season, the Cowboys were more than respectable through the first seven games this year. However, the Redskins had two 80-yard scoring drives in the second half, and Dallas couldn’t get a stop in overtime.

–RB DeMarco Murray extended his NFL record with his eighth consecutive 100-yard rushing game to open a season. The NFL’s rushing leader ran for 141 yards on 19 carries, which also put him over 1,000 yards on the season for the second time in his career. Murray also caught four passes for 80 yards.

–QB Tony Romo threw a touchdown pass in a 36th consecutive game, tying Brett Favre for the fifth-longest streak in NFL history. Romo left the game midway through the third quarter after being sacked. He returned late in the fourth after receiving an injection in his surgically repaired back, and he said he expects to be ready for the Cowboys’ next game.

–LB Justin Durant sustained an arm injury early in the fourth quarter and didn’t return. Owner Jerry Jones said Durant has a torn biceps, adding, “That’s probably going to be it for him.”