Washington Redskins Coach Mike Shanahan came away from his review of Kirk Cousins’s performance against the Atlanta Falcons with a sense of encouragement but maintained that Robert Griffin III remains the franchise quarterback. Shanahan seemed to leave the door open for a competition down the road, however, stating that such a situation would only make Griffin — and the Redskins as a whole — better.

“The thing that you want on your football team is you want competition — legitimate competition. The better players you have, the more people compete,” Shanahan said. “When you look behind your shoulder and you know that guy is pretty good, that makes you work a little harder in the offseason. It makes you work a little harder during the week. And when there is no depth, where there is no competition, you look over your shoulder and say, ‘Hey, I don’t have to push myself that hard.’ So I’ve always believed that true competition is the biggest motivator you can have regardless of who you are because everybody knows that we’re going to play the best players at the end of the day.”

Cousins made the second start of his career Sunday — the first with Griffin healthy. Shanahan decided last week he should shut down a struggling Griffin for the final three weeks of the season, calling it important for the quarterback to make it through the season healthy so he could work on his development in the offseason.

Griffin’s deactivation set up Cousins with the opportunity to showcase his skills in an expanded capacity.

Cousins took advantage by completing 29 of 45 passes for 381 yards, three touchdowns and two interceptions. Cousins directed a 13-play, 80-yard scoring drive that cut the Falcons’ lead to one point with 18 seconds remaining.

The Post Sports Live crew discusses what actions Redskins owner Dan Snyder should take in response to the team’s numerous failures this season. (Jayne Orenstein/PostSportsLive/The Washington Post)

Washington went for the victory with a two-point conversion attempt. But Cousins’s pass fell incomplete in the back of the end zone, and the Redskins fell, 27-26, dropping to 3-11.

With Sunday’s outing and a 329-yard performance last season against Cleveland , Cousins became the first Redskins quarterback since the AFL-NFL merger to throw for 300 yards in each of his first two starts, according to Elias Sports Bureau.

Cousins had an impressive first half against the Falcons, completing 13 of 20 passes for 248 yards and two touchdowns. He struggled in the third quarter and early in the fourth, throwing two interceptions. Cousins finished the game on a strong note, going 10 for 13 for 80 yards and a touchdown on the final drive.

“Kirk did do a good job, especially at the end of the game. Even at halftime, I thought he did some good things,” Shanahan said Monday. “That’s part of the maturation process of the quarterback. You like to see him in live situations. You can practice it all the way through [organized team activities]. You can practice it through minicamps, which he got a lot of reps. But can he take it to the field? I was pleased with how he handled himself.”

Cousins did get all of the first-team snaps in the offseason and training camp while Griffin rehabilitated from knee surgery. Cousins made two starts in the preseason but missed the final two games because of a foot injury.

He had seen time in only two games this season — relieving Griffin in losses to Denver and Kansas City. Cousins then took over as the starter this week. Despite not getting the win, he impressed his teammates.

“I know how hard it is to have a full 14 weeks off, and really he got hurt early in the preseason, so he had to step right in,” backup quarterback Rex Grossman said. “The way he played, especially in the first half, I thought it was amazing. It was a gutsy performance by him. There was a lot of chaos earlier in the week.

“He was making very quick decisions. He was making right decisions, getting the ball out quickly and accurately. He was conducting the offense pretty much like a vet. He hasn’t really played a lot, but the offense for the most part looked smooth. It’s hard to step in as the backup late in the year, period. . . . I thought he did a hell of a job.”

Despite his promising numbers, Shanahan did his best to temper the expectations of Cousins going forward.

“We’ve had one game. Let’s not get carried away with numbers, okay?” Shanahan said. “We’ve had one game where we lost the game. Let’s take a look — we’ve got Dallas, we’ve got the Giants. We talked about our game plan coming in. He gives Robert a chance to be healthy going into the offseason program. It gives Kirk some valuable experience as a football player. We’ve got some competition at a lot of different positions for next year, and the best players will play.”