The Washington Redskins closed the home-field portion of their schedule Sunday in the same manner in which they opened it: with a demoralizing loss to an NFC East rival.

Again, the division’s last-place team made many mistakes down the stretch, which helped the Dallas Cowboys rally for a 24-23 victory. The Redskins squandered a nine-point fourth-quarter lead and gave up the go-ahead score on fourth down with less than 70 seconds to play.

After Dallas quarterback Tony Romo teamed with running back DeMarco Murray on a 10-yard touchdown pass, the Redskins got the ball back on their 13-yard line with 1 minute 1 second remaining in the game. But quarterback Kirk Cousins, who struggled in his second start of the season, wasn’t sharp.

The Cowboys quickly regained possession, and Romo kneeled once to run out the clock, completing a victory that kept them in the hunt with the Philadelphia Eagles for the NFC East title. The Eagles defeated the Redskins in the season opener at FedEx Field.

For the 3-12 Redskins, their last game at FedEx in 2013 provided yet another reminder that much must change for them to improve in 2014. Foremost, though, the Redskins need to get it straightened out at quarterback. Their self-inflicted quarterback controversy has been among the worst developments in a disastrous season. Let’s start there.

A step backward

Cousins has been mostly effective directing the Redskins’ offense. He did many things well — leading receivers, cycling through progressions and making good decisions in the pocket — in place of Robert Griffin III during a Week 15 loss to the Atlanta Falcons. Against the Cowboys, however, Cousins wasn’t impressive.

He completed only 21 of 36 passes for 197 yards. Often, Cousins wasn’t accurate. Late in the first half, Cousins threw behind wide receiver Santana Moss, who was running uncovered deep in Dallas territory. The ball bounced off Moss’s hands and was intercepted.

Wide receiver Pierre Garcon had 11 catches and 144 yards and combined with Cousins on a touchdown. Garcon could have had a much bigger performance if Cousins hadn’t led him too much on several plays. On the final drive, Cousins had three straight incompletions as the Redskins faded away quietly.

Dallas ranks last in the NFL in defense. Redskins receivers rarely encountered tight coverage on short, intermediate or deep routes. The Falcons’ secondary isn’t particularly strong, either. A lot is unknown about Cousins.

Griffin was the 2012 NFL offensive rookie of the year. He had reconstructive knee surgery and wasn’t in top form this season.

But remember: Washington invested four high-round picks in Griffin, and he proved he can be special. The Redskins need to do everything they can to help Griffin rebound next season.

A solo act

With one game remaining, Garcon has established a single-season Redskins record with 107 receptions. Art Monk held the previous top mark, catching 106 passes in 1984.

Monk’s personal-best season occurred for a team that went 11-5 and finished first in the division. Although the Redskins relied on Monk in 1984, they had a balanced offense and a strong roster. Garcon needs more help.

The biggest reason Garcon has so many catches is that Cousins and Griffin lack confidence in the team’s other wide receivers.

Of Cousins’s 36 passes against the Cowboys, half were thrown in Garcon’s direction. During the season, Griffin’s frustration grew because opponents regularly double-teamed Garcon and the other wide receivers failed to break away from single coverage.

Attempting to free Garcon, offensive coordinator Kyle Shanahan regularly called screens and gimmick plays for him. Kyle played it straight against the Falcons and Cowboys, who are awful in the secondary.

On many routes the past couple of weeks, Garcon was alone and produced big yardage after catches. Unfortunately for Garcon, most teams are better in the defensive backfield than the Falcons and Cowboys.

The Redskins need another wide receiver capable of taking some of the pressure off Garcon. Acquiring one should be a top priority in free agency.

Starting over on defense

Seven of the 11 players who started on defense against Dallas (8-7) can become free agents after the season. And the Redskins have few impact players on defense, which has been painfully apparent all season and was again as the Cowboys rallied late in the game.

The Redskins have to get better along their defensive front. In a 3-4 defense, the nose tackle and ends must command double teams to free linebackers to make plays. The Redskins’ linemen are just average.

At outside linebacker, Ryan Kerrigan, who had a sack Sunday, has been slowed by injuries. Although Brian Orakpo finished strong after a slow start, is he worth a big contract?

In the secondary, cornerback Josh Wilson has been a major disappointment. On the Cowboys’ game-winning drive, Wilson slipped while trying to cover Dallas wide receiver Terrance Williams, who gained 51 yards. Five plays later, Romo connected with Murray.

Coach Mike Shanahan’s decision to change the defensive philosophy hasn’t paid off. Even if Shanahan returns next season, perhaps the Redskins should consider switching back to a 4-3 alignment. It couldn’t produce results worse than the past four years.

The takeaway

Mike Shanahan has clinched the worst record of his coaching career. The Redskins must defeat the New York Giants on the road next week to avoid going 0-8 in the second half of their schedule. If this is progress, what does failure look like?

For more by Jason Reid, visit washingtonpost.com/reid.