Normally, knocking an opponent’s starting quarterback and workhorse running back out of a game would seem like a recipe for success.

The Washington Redskins did both to the Minnesota Vikings Saturday afternoon, but still came up short, outdone by a mobile substitute quarterback, an inability to stop the run, penalties and turnovers in a 33-26 Christmas Eve defeat at FedEx Field.

With the loss, Washington fell to 5-10 on the season and clinched a third consecutive 10-loss season for only the second time in franchise history. The only other time the team reached that low point was from 1993 to 1995. The Redskins, who finish their season next week at Philadelphia, closed out the home portion of their schedule with a 2-6 record — their worst mark at FedEx Field during Daniel Snyder’s 12-season tenure as owner.

The Redskins, playing in front of a crowd announced at 68,370, wasted a career day by rookie running back Evan Royster, who gained 132 yards on 19 carries in the first start of his NFL career. Royster filled in for rookie Roy Helu, who was sidelined by injury.

Washington failed to overcome eight penalties for 64 yards and a fumble and interception by quarterback Rex Grossman as its turnover streak extended to 29 consecutive games — a league high.

Instead of struggling without quarterback Christian Ponder, who left the game three plays into the third quarter with a concussion, and star running back Adrian Peterson, who suffered a serious knee injury on the first play of the second half, Minnesota received a spark from backup quarterback Joe Webb and running back Toby Gerhart.

Webb threw for 84 yards and two touchdowns and rushed for 34 yards and a touchdown. Gerhart rushed for 109 yards on 11 carries, leading the Vikings, who racked up 241 yards on the ground.

“When Ponder and Peterson both went out, Joe Webb came in and added a different dimension for them offensively, with the bootlegs and the quarterback keeps and the option — stuff that we knew they would run,” said inside linebacker London Fletcher, who had 17 tackles and the sack that knocked Ponder out of the game. “But I guess today we weren’t able to defend it as well as we’d like to. Gerhart, he ran hard and broke some tackles.”

With the win, Minnesota improved to 3-12 on the season and snapped a six-game losing streak.

The Vikings’ chances didn’t seem good early in the third quarter. On the first play of the third quarter, with the score tied at 10, rookie safety DeJon Gomes met Peterson in the hole and delivered a low tackle to Peterson’s left knee that left the Viking writhing on the ground in pain. The back, who had 12 carries for 38 yards and a touchdown, had to be helped back to the sideline and, a short time later, headed to the locker room on a cart. The Vikings announced late Saturday night that Peterson tore his left anterior cruciate ligament.

On the very next play, Fletcher rocked Ponder on a sack for a one-yard loss. Ponder’s head snapped backward, but he remained in the game for one more play — an incompletion to Gerhart. As his team punted the ball away, the rookie quarterback headed to the locker room, where a concussion was diagnosed.

Those two losses didn’t seem to affect the Vikings, however, as Webb passed for two touchdowns and rushed for another to lead his team to victory.

After Washington took a 13-10 lead with a 53-yard Graham Gano field goal, Gerhart rumbled 67 yards to put Minnesota in scoring position. Two plays later, Webb rolled out and scored on a nine-yard run as Minnesota took a 17-13 lead.

The Redskins answered, however, with a seven-play drive that featured four completions from Grossman to wide receiver Jabar Gaffney. The former University of Florida teammates connected on the last three plays of the drive — including a four-yard touchdown pass that Grossman flicked to Gaffney, who made a one-handed grab to briefly put the Redskins ahead.

But Webb answered by completing a 17-yard touchdown pass to tight end Kyle Rudolph to put the Vikings up 23-20. Another Gano field goal followed, before Webb marched Minnesota downfield on a drive that included a 36-yard completion to wideout Percy Harvin and a 23-yard pass to Devin Aromashodu. He connected with Harvin on an eight-yard touchdown toss that put Minnesota up 30-23.

Then things went south for Washington’s offense.

Wide receiver-return specialist Brandon Banks had a 59-yard touchdown run nullified by a holding call on fullback Darrel Young. It was the second costly penalty of the game for Young, who in the first half lined up in the neutral zone on the punt return team to give the Vikings a first down on a drive that ended with Minnesota scoring a touchdown.

On the very next play, Grossman fired a 23-yard interception to Minnesota safety Mistral Raymond, badly overthrowing wide receiver Santana Moss.

The play continued one dubious streak and ended another. It marked the 11th straight game in which Grossman had thrown at least one interception. And it was the first time in 10 games that the Vikings had come up with a pick.

“It’s what wins you games and loses you games,” Redskins Coach Mike Shanahan said of the miscues. “A 60-yard play that’s turned back, you have a team stopped and jump offside and you give them seven points there. We turned the ball over at the 20-yard line and gave them a field goal there. That’s the difference between winning and losing.”

The Vikings got a field goal off Grossman’s turnover and extended their lead to 33-23. Washington got a 47-yard field goal from Gano — his fourth of the day — to pull within 33-26 with 1 minute 25 seconds remaining. The Redskins’ defense held and got the ball back for a last-minute drive. But a miscommunication between Grossman and center Will Montgomery led to an illegal motion call on Grossman, who was moving when Montgomery snapped the ball. That backed up Washington from the Minnesota 48 to the Washington 47. Two plays later, Grossman’s Hail Mary pass on third and four fell incomplete.

Minnesota took a 10-0 lead to start the game, getting on the board first thanks to Grossman’s 23rd turnover of the season.

Vikings defensive end Brian Robison stripped Grossman of the ball as he blitzed and recovered the ball at the Washington 20. Ryan Longwell hit a 36-yard field goal to put Minnesota up 3-0 with 7:11 left in the quarter. And on the first play of the second quarter, Adrian Peterson scored from a yard out.

Finding themselves in a 10-point hole, the Redskins found a spark and went 60 yards in seven plays to score their first touchdown of the game — a five-yard pass from Grossman to Donte Stallworth. Gano later hit a 26-yarder to tie the score at 10.

“When you do something well, you got to finish those drives with touchdowns. Too many times we settled for field goals,” Grossman said. “We did get a couple touchdowns in, but we need to have more in the first quarter as well.”

More on Redskins vs. Vikings:

Jason Reid: Redskins offer glimmers of hope

Summary and stats: Vikings 33, Redskins 26

Fletcher has a season-high 17 tackles, leads NFL

Gaffney sets career high in receiving yards