PHILADELPHIA — Last week, when a certain Jimmy Johnson said he was not yet sold on the Philadelphia Eagles, despite their 8-0 start, guard Landon Dickerson was baffled.

“Who’s this guy?” Dickerson asked his teammate Jordan Mailata, per The Philadelphia Inquirer. “The NASCAR driver?”

No, Mailata explained. This was Jimmy Johnson, who was behind the wheel for two Super Bowl victories while coaching the Dallas Cowboys in the 1990s. Not Jimmie Johnson, who wears the helmet of a different sport and makes his living turning left.

Perhaps Dickerson, 24, could be excused for the confusion. He was not yet born when Johnson won his last Super Bowl ring. Still, Johnson, now a Fox commentator, had a point. His skepticism arose from the Eagles’ tendency to score a flurry of points early in games, only to struggle later when opponents grew more familiar with and resistant to Philadelphia’s run-pass option offense led by quarterback Jalen Hurts.

This torpor was evident again in the Eagles’ first defeat of the season, a 32-21 loss to Washington on Monday night. Philadelphia took a 14-7 lead in the first 13½ minutes, scoring the touchdowns on a short run and a jump-pass by Hurts. Washington ran off the next 16 points to take an insurmountable lead, and Philadelphia scored only once more, in the third quarter. After scoring 133 points in the second quarter of its first eight games, the Eagles managed zero on Monday.

It was a collective defeat, caused by penalties, uncharacteristic fumbles by a team leading the N.F.L. in turnover differential, an interception thrown by Hurts at the Washington 14-yard line and the inability of Philadelphia’s defense to stop a Washington offense that controlled the ball for 40 minutes and 24 seconds of the game’s 60 minutes. On a chilly night, there was nothing crisp about Philadelphia but the weather.

Futility continued until the game’s final play, when the desperate Eagles began lateraling the ball and Washington defensive end Casey Toohill scooped up a backward toss by Philadelphia receiver Devonta Smith near the goal line and sauntered into the end zone.

Philadelphia’s loss guaranteed that for the 50th consecutive year — since the 1972 Miami Dolphins — the N.F.L. will not finish a season with an undefeated team.

“We played like crap,” Philadelphia Coach Nick Sirianni said bluntly. “We made our own luck today and it was bad.”

Because of the vagaries of scheduling, the Eagles were playing only their third game in 29 days. Rust, though, did not explain Philadelphia’s familiar offensive lethargy as the game progressed or Washington’s ability to control the ball with long, sustained drives.

The Commanders (5-5) converted 12 of their first 16 third-down plays. Quarterback Taylor Heinicke (12 of 21 for 145 yards) punctured the Eagles’ zone defense, hitting receivers as they ran freely over the middle and throwing precise passes along the sidelines.

Kicker Joey Slye hit field goals of 44, 58, 32 and 55 yards with unblemished accuracy. And the Commanders, well, commanded the game with 152 rushing yards. Philadelphia’s defensive line has been left susceptible by an ankle injury to its best run-stuffer, Jordan Davis, the 6-foot-6 inch, 336-pound rookie. Running has become a prescription for the Eagles’ opponents in seeking victory.

“That’s going to happen until we stop it,” said defensive end Brandon Graham.

The victory continued an impressive recovery for Washington’s rookie running back, Brian Robinson, who was shot in the right leg and knee on Aug. 28 in what police said was an attempted robbery or carjacking while he was out to dinner. Robinson underwent surgery and missed the Commanders’ first three games, including a 24-8 loss to Philadelphia on Sept. 25.

Monday night, Robinson rushed for 86 yards on 26 pounding carries. In the second quarter, he dragged Philadelphia defenders for 11 yards on one play, shedding them as if they were layers of clothing, then cleverly reached over the goal line on the next down to put the Commanders ahead to stay, 17-14.

Even with their disjointed play, though, the Eagles had their chances to salvage Monday’s game after an 11-yard touchdown pass from Hurts to Smith drew them within 23-21 on the first play of the fourth quarter. But fumbles squandered final opportunities to win.

Tight end Dallas Goedert coughed up a pass as the referees appeared to miss a face-mask penalty. Slye then drilled a 55-yard field goal to put Washington up 26-21, forcing Philadelphia to score a touchdown to prevail.

On Philadelphia’s next possession, receiver Quez Watkins caught a 50-yard pass over the middle, only to be stripped of the ball at Washington’s 20-yard line. An unnecessary roughness penalty by Graham on the kneeling Heinicke with 1:38 remaining kept the ball out of Philadelphia’s hands until the final frantic and distressed seconds.

“We lost it together,” Sirianni said. “Offense, defense, special teams, coaching. We lost it together.”