Case Keenum took a seven-step drop, cocked his arm back and whipped a pass deep down the middle of the field against the Philadelphia Eagles on Sept. 8.

His target was Terry McLaurin, who created more than enough separation from his defender as the ball sliced through the air. A completion would have resulted in a touchdown, which would have given Washington back the lead in the third quarter of the Week 1 contest. It would have been the second time in the game that Keenum and McLaurin connected for a long score. 

But as the ball dropped towards the Lincoln Financial Field grass, McLaurin could not catch up. The pass landed a few yards in front of the third-round rookie for an incompletion.

"I just let it go probably a hare too soon," Keenum said after the team's 32-27 defeat. "I want that one back."

While Keenum's misfire wasted a prime opportunity to seize back momentum, it was one of the few mistakes he made in his Redskins debut. Keenum completed 30 of his 44 passes for 380 yards. He threw for three touchdowns and did not commit a turnover. He was only sacked once. 

Keenum, who emerged from a summer-long quarterback competition as the starter, helped carry an offense with a nonexistent running game and frequently penalized offensive linemen. He was highly productive with an inexperienced group of wideouts and without one of the team's biggest playmakers, tight end Jordan Reed.

Against the Eagles, Keenum validated the team's decision to go with the veteran signal-caller under center. His next test will come Sunday against his home-state franchise, the Dallas Cowboys.

"He was efficient with the ball," head coach Jay Gruden said of Keenum. "He made some good decisions, some good, pure progression reads. He threw the ball accurately. He took a couple shots and they weren't there. He checked it down to Derrius Guice a couple times, which was great to see surrounded by the pocket. I thought he played an excellent game for his first time in a Redskins jersey."

Keenum, too, was largely pleased with the efforts of himself and the rest of the offense in Philadelphia. He thought the unit handled itself well in a chaotic environment, limiting pre-snap penalties while accumulating 398 yards of total offense. Eight different receivers caught Keenum's 30 completions, with four wideouts catching at least four passes at a variety of depths.

On the first drive, Keenum located tight end Vernon Davis on a routine drag route that resulted in a 48-yard, highlight-reel touchdown. Two possessions later, Keenum located McLaurin running free with no help over the top. "Those are plays you dream about as a quarterback," Keenum said afterwards, and he capitalized on the occasion, delivering a pristine pass for a 69-yard catch-and-run touchdown. 

By halftime, Keenum had already racked up 257 yards passes and threw six incompletions on 22 attempts. More importantly, the Redskins held a 13-point advantage.

"[Keenum] spreads the ball around to different guys," said Paul Richardson, who made four receptions for 36 yards. "He showed he can throw the deep ball once to Terry [McLaurin]. He even did well when we changed the tempo, getting guys lined up, getting the play out, communicating. He did well. He played like a vet."

In the third quarter, however, the offense unraveled. After Philadelphia's eight-minute touchdown drive to start the half, Washington went three-and-out in fewer than three minutes. Following the Eagles' go-ahead score, Keenum threw three incompletions. It took just 30 seconds of game action for the Redskins to punt again.

"There was just some crucial times where we needed to step up, our defense needed us to step up and we didn't," Keenum told reporters during his weekly press conference Wednesday. "Just like I said after the end of the game, we didn't play complementary football there in the third quarter when we needed to. But, we're looking ahead. We've moved on and we're excited about another great test this week."

Despite having never played Dallas -- one of three teams he has yet to play in the regular season since entering the league in 2012 -- Keenum is plenty familiar with the franchise. 

He grew up in Texas and has plenty of friends and family who prefer silver and blue to burgundy and gold. "They got a big box of Redskins gear this year," said Keenum, who Washington acquired in a trade this offseason. "But they have to hide it from all their friends." Additionally, Keenum has fond memories of going to Cowboys games as a kid and participating in punt, pass and kick competitions -- plus a few high school playoff games -- at the old Texas Stadium.

As for the current Cowboys team, Keenum understands the challenges. In his mind, the Cowboys have a "very dangerous" defensive front, Pro Bowl linebackers and an experienced secondary. Their depth allows them to effectively switch defenses and coverages.

This will present a challenge for the Redskins, but not one they cannot handle. Keenum remains confident in himself and his teammates. He referred to Gruden and offensive coordinator Kevin O'Connell as "great game planners" before adding, "I haven't been around many that do it as well as they do."

Keenum knows they'll put him in positions to succeed, just like they did in the first half against Philadelphia. From there, it will be up to him to build on a promising debut with a solid second act.

"I'm really excited to here in front of our home fans especially playing the Cowboys," Keenum said. "I think traditionally, historically, this has got the makings or has got a strong argument to be one of the best rivalries in all of sports. I'm excited to be a part of that. It's pretty cool. I'm excited to go out there and sling it around a little bit."