OTTAWA — Marcus Thigpen still has plenty of juice left in his 31-year-old legs.

Thigpen ran for 169 yards and a key TD to lead Saskatchewan to a record-setting 31-20 East Division semifinal win over the Ottawa Redblacks on Sunday before a TD Stadium sellout of 24,107. Thigpen joined the Roughriders in September after being out of football for roughly two years and started with both Marshall Cameron and Trent Richardson on the injured list.

"I felt like I stopped playing too early and felt like I still had a lot left in the tank," said Thigpen, donning a T-shirt with the Superman logo. "I was still running track with my high school coach and I knew I still had the speed.

"I stayed in the weight room, I knew I had the size and strength. I just felt like I missed it and wanted to come back."

So the five-foot-nine, 195-pound Thigpen, a Detroit native, reached out to Riders' starter Kevin Glenn, who also hails from Detroit, via Instagram. Glenn relayed that message to Chris Jones, the Riders head coach/GM, and the rest, as they say, is history.

"We're both from Detroit so we've always kept in touch," Glenn said. "He mentioned he was trying to get back into the game and I went to coach Jones and he was like, 'Right now, get him on the phone.'

"I've got to get a percentage from (Thigpen) now since he's back."

But Thigpen has his own repayment in mind: Helping Glenn, a 15-year CFL veteran, win his first Grey Cup championship. Saskatchewan will face the Toronto Argonauts on Sunday in the East Division final with the winner advancing to the championship game.

However, history isn't on the Riders' side. They'll try to become the first crossover team to reach the Grey Cup since the rule was adopted in 1996.

"I know it's never been done before . . . but anything is possible," Thigpen said. "I've never won a championship in football in my life and I want it as bad as (Glenn) does.

"That's one of our motivations . . . he deserves it."

Jones was surprised when Glenn told him about Thigpen's desire to resume playing.

"Well we didn't actually know he was interested," Jones said. "KG came in and said he'd reached out to him and I'm like, 'You've got to be kidding me?'

"So we brought him in and it wasn't long until we could say he still had some juice."

Saskatchewan and Ottawa combined for three touchdowns on the game's first three possessions. That set CFL playoff records for fastest two TDs (four minutes seven seconds); fastest three touchdowns (5:54); and first time the opening three possessions resulted in a touchdown.

Thigpen punched Saskatchewan's ticket to the East final with a 75-yard TD run in the third quarter. It came immediately after Ottawa settled for Brett Maher's 22-yard field goal that cut the Riders' lead to 21-11 following a fumble recovery at the Roughriders' 19-yard line.

"It was an inside zone play and I kind of just crossed the line to the left and saw there was nothing there," Thigpen said. "I bounced back and the hole was right there.

"I saw daylight and knew I still have a little juice in these legs left so I just ran as fast as I could and got the score."

Ottawa head coach Rick Campbell wasn't surprised by Thigpen's performance.

"He's a real good player, explosive," he said. "The thing with that guy is if you give him space he's fast so he can turn that good play into a huge play as you saw in the game."

Glenn finished 18-of-28 passing for 252 yards and a TD in his 12th career playoff start. He also had a one-yard scoring run.

"The biggest thing was we did what we wanted to do, which was come out and start fast," Glenn said. "Just making it a game where we don't worry about Ottawa's defence or anything, just make sure we're doing what we're supposed to do.

"To be on the verge of doing that (reaching Grey Cup as crossover team) and making history is exciting. We've got to enjoy this one and then put it to bed and get into our books and film on Toronto. We've got a tough task."

Ottawa's Trevor Harris, is his first career playoff start, was 37-of-60 passing for 457 yards with two TDs and two interceptions. Diontae Spencer had eight catches for 142 yards (both game highs) and a touchdown.

But Ottawa killed itself with two key turnovers: Samuel Eguavoen's interception to halt a potential scoring drive at the Riders' 10-yard line in the first and Ryan Lindley losing a fumble in the second at the Redblacks 37-yard line.

"We turned the ball over twice on their side of the field which was killer," Campbell said. "But there was still a lot of opportunities to overcome that.

"We never found a way to make key plays in big moments of the game. They made plays today, we didn't. That's the bottom line."

Vernon Adams Jr. and Bakari Grant had Saskatchewan's other touchdowns. Tyler Crapigna added the converts and a field goal.

Juron Criner scored Ottawa's other touchdown while adding a two-point convert. Maher booted two field goals.