REGINA — Zach Collaros was due.

Defence and special teams had been carrying the Saskatchewan Roughriders through much of the season.

But on Sunday in the Labour Day Classic, Collaros came through, engineering two fourth-quarter touchdown drives to lift the Riders to a 31-23 comeback victory over the Winnipeg Blue Bombers and a third consecutive win for the green and white.

"Our defence has been holding us in games all year. This was our turn," said Saskatchewan's Marcus Thigpen, who had a touchdown reception from Collaros in the decisive fourth quarter.

Trailing 20-17 after three quarters, the Riders' offence hit its stride and capped a six-play, 75-yard scoring drive with Thigpen's touchdown. Saskatchewan took a 24-20 lead, one it wouldn't relinquish.

Winnipeg answered with a Justin Medlock field goal with seven minutes remaining to pull to within one at 24-23, but that was as close as they would get.

Collaros put the game out of reach when he marched the Riders on a late scoring drive, one that was highlighted with a 39-yard pass to Jordan Williams-Lambert that set up the Riders at the Winnipeg three-yard line.

Two plays later, Nick Marshall, a defensive back and short yardage specialist, scored on a one-yard run. It was Marshall's second touchdown of the game.

"That was really big for us. It took a lot of pressure off the defence," said Saskatchewan's defensive lineman Charleston Hughes. "When your offence can put up points like that, it's a soothing feeling.

Collaros completed 18 of 30 pass attempts for 250 yards, one touchdown and an interception.

"It's a big boost for everybody," Hughes added. "I think our offence it coming along quite well. Zach is having one heck of a season since he has been back."

The Riders (6-4) have won 12 of the past 13 Labour Day contests versus Winnipeg and three of four games since Collaros returned from the six-game injured list. They moved into a second-place tie with the Edmonton Eskimos and are just four points behind the first-place Calgary Stampeders (8-1), who will take on the Eskimos on Monday.

The Blue Bombers (5-6) have dropped three straight. They'll host the Riders next weekend in the Banjo Bowl.

Winnipeg dictated Sunday's contest through much of the first half, led by running back Andrew Harris. The league's leading rusher exploded for 105 rushing yards over the first two quarters and Winnipeg held a decisive lead in total offence, outgaining the Riders 230-97 at halftime.

But quarterback Matt Nichols and the Winnipeg offence saw their big gains dry up in the second half. They could muster just two field goals from kicker Justin Medlock.

"This was a hard one to let slip away," Nichols said. "For me personally, I need to be better. We had the ball a couple of time when we down three late and we couldn't get anything going. I have to find a way to get us going."

Kyran Moore, playing in just his second game with the Riders, ignited the sold-out crowd late in the second quarter with a 65-yard punt return for a touchdown, a score that put the home side ahead 14-10.

Darvin Adams and the Blue Bombers picked up a late score in the first half when the receiver hauled in a 10-yard pass from backup quarterback Chris Streveler.

Winnipeg led 17-14 at the half.

Harris finished the game with 158 rushing yard on 15 carries. Nichols, who had thrown for more than 300 yards in each of the past two Labour Day games, managed just 166 yards passing. He was intercepted twice and sacked three times.

"They did what they do," Nichols said of the Saskatchewan defence. "Overall, they made more plays in the end and that's what it came down to."

With one sack on Sunday, Hughes has recorded at least one sack in each of the past eight games. He leads CFL with 13 sacks.

Kenbrell Thompkins had the other touchdown for Winnipeg, who also got three field goals from Medlock.