Alfred Morris ran for a season-high 121 yards in Washington’s victory over San Diego. The Redskins rushed 40 times for 209 yards in the win. (Jonathan Newton/The Washington Post)

The Washington Redskins got their groove back on offense Sunday thanks to a renewed emphasis on the running game, accompanied by a number of creative wrinkles from offensive coordinator Kyle Shanahan’s playbook.

For the second time this season, the Redskins ran the ball at least 40 times and topped the 200-yard mark on the ground en route to victory. Washington had 40 carries for 209 yards in the 30-24 overtime win over San Diego.

The only other time the Redskins’ run game eclipsed the 40-carry, 200-yard mark came on Oct. 20 against Chicago, when they had 43 carries for 209 yards in a 45-41 win over the Bears. The Bears game saw the return of Robert Griffin III as a weapon in the zone-read attack. His 11 carries for 84 yards in Week 7 complemented Alfred Morris’s 19-carry, 95-yard effort, and Roy Helu Jr. served as a third weapon with 11 carries for 41 yards and three touchdowns.

On Sunday, Morris had his best game of the season, carrying the ball 25 times for 121 yards and a touchdown. Another five players combined for 88 more rushing yards.

The Redskins again broke out the option attack against the Chargers, but they added a twist, using the triple option to keep their opponents off balance.

Three times Washington went to the triple option — first on Washington’s third offensive play when Griffin drew safety Eric Weddle to him and then pitched to tight end Jordan Reed, who had come in motion, set up in the backfield and proceeded to pick up 18 yards on the play.

In the third quarter, the Redskins went back to the play, but this time using slot receiver Santana Moss, who trailed Griffin as he rolled out to the right, drew safety Marcus Gilchrist to him and then pitched to Moss, who also picked up 18 yards on his run.

“We were just trying to switch it up,” Griffin said of the plays. “I don’t want to go out there and have people know what you’re doing all the time, so as an offense, you have to switch things up, keep the defense off balance and that’s what we did as an offense. The one thing you don’t want to do is become predictable. Whenever we’ve been on throughout the whole season, we’ve done a better job of just mixing things up – run, pass, giving them different looks. Give them something to think about.”

Until Sunday, the Redskins hadn’t featured much of the triple-option attack since last season. They had shown that look a couple of times this season, but didn’t run any of the pitches.

But that didn’t represent the only wrinkle added to the playbook this week.

The Redskins also sported a couple of unbalanced line formations against San Diego. On one play, tight end Logan Paulsen line up at the end of the line next to left guard Kory Lichtensteiger and left tackle Trent Williams lined up at the opposite end, next to right tackle Tyler Polumbus. Chargers defenders appeared to be keying on the right side of the line, but Washington ran a handoff to Morris, who ran through a hole created by Paulsen and Lichtensteiger on the left side and gained 26 yards — his longest run of the game.

“It’s all part of the game plan,” Coach Mike Shanahan said. “The key is to have it in your offense. You don’t have to run it a lot, but if you do have it in there and you feel like it’s going well, you can keep on running it. And if not, it’ll open something else. I think the more you can do as an offense to keep people off-balance, the better off you are.”

With an effective running game, Washington’s pass attack benefitted. The Chargers didn’t blitz as aggressively as other opponents have because they had to respect the run, and for the first time all season, the Redskins’ offensive line didn’t surrender a sack. Griffin completed a season-best 71.9 percent of his passes.

The Redskins also excelled on third downs — usually an area of weakness this season — converting 12 of 17 attempts for first downs. Griffin completed 6 of 10 third-down passes for first downs, and he also had a 10-yard run on third and nine.

“The great quarterbacks are the guys that are consistent on third down, and I thought Robert had his best game of the year,” Shanahan said. “Any time that you’re over 70 percent in third down conversions, your quarterback is playing extremely well. And that’s what you’ve got to do.”