The educated Washington Redskins fans among a Christmas Eve crowd of 68,370 at FedEx Field knew, once Brandon Banks joined the offensive huddle, something was up. Banks is a return specialist by trade, and when he takes the field on offense, trickery usually ensues.

“I’m more anxious to get out there to make a big play for us, because I feel like that’s what we needed,” Banks said. “That’s what I feel like I put out there.”

It appeared, moments later, that Banks had provided that big play. And indeed, what happened next — over two snaps and 34 seconds off the play clock — all but decided the Redskins’ 33-26 loss to the Minnesota Vikings Saturday afternoon.

Banks did his job. When he entered the game for his only offensive snap, the Redskins trailed by a touchdown midway through the fourth quarter and had the ball at their 41-yard line. He had appeared only sparingly on plays from scrimmage this year, throwing a 49-yard touchdown against New England in Week 14. He didn’t have a rushing attempt. He had not been targeted on a pass, much less come up with a catch.

On Saturday, though, he lined up on the right side of the formation, and took a reverse handoff from quarterback Rex Grossman. He headed toward the far left sideline. His view?

“Green grass is what I saw,” Banks said.

When he reached the sideline, he cut upfield. The 5-foot-7 wide receiver is in the NFL for one reason: speed. When he planted his foot, he had the entire Vikings defensive unit beat. And just after he reached the end zone, he leaped into the stands, celebrating what looked to be a tying touchdown.

Yet back at the line of scrimmage, Grossman was already getting ready for second and 10.

“The flag almost hit me,” Grossman said.

The penalty, it turned out, was a holding call against fullback Darrel Young, who hooked his arm around devastating Minnesota defensive end Jared Allen.

“Usually, you don’t have a holding call on a reverse play,” Redskins Coach Mike Shanahan said. “Everybody’s going the other way. So that’s quite unusual, to start with.”

The call, it seemed, could have gone either way. Allen, who leads the league in sacks, isn’t normally hauled down by an opponent using one arm. Young, though, was more than contrite afterward. His job on the play?

“Truthfully, it’s just fake and let Banks come around,” Young said. “It’s my fault. I take full responsibility for it. . . . I cost the team the game, and I got to face the responsibility.”

Even after Banks realized what had happened — “That’s the worst feeling ever,” he said — the Redskins had more than a chance. They had moved the ball effectively, finishing with 397 yards of offense, and had every reason to believe, with a little less than eight minutes to go, they could tie the score.

On second and 10 from the 32, Grossman dropped back to pass. He looked to veteran Santana Moss on his right. Moss found a soft spot in the defense, but Grossman badly overthrew him.

“It was high,” Grossman said. “I could elaborate, but it’s pretty simple.”

The ball settled neatly into the hands of Vikings safety Mistral Raymond, the first interception of Grossman’s day. That, in itself, is notable. Grossman has now started 15 games as a Redskin, including 12 this season. He has gone without an interception just once, in a season-opening victory over the New York Giants. Toss in his first quarter fumble, which came as he was sacked by Vikings defensive end Brian Robison, and he now has 24 turnovers in a dozen games.

Raymond’s return went to the Washington 24. The Redskins defense held Minnesota to a field goal, but at 33-23, the Redskins trailed by two scores with 4:10 left. The game had swung.

“That’s the difference between winning and losing,” Shanahan said. “That’s what you’ve got to do. You can’t beat yourself. You don’t win the turnover war and you make a couple of those penalties. . . . You got to work, as a football team, to eliminate those things.”

Two snaps, one apparent touchdown, one penalty, one misguided throw, one interception — 34 seconds in which the Redskins sealed their 10th loss of the season.

“It’s tough,” Grossman said. “We need to win tough, close games consistently.”