A shockwave was sent around the Canadian Football League on Sunday night at Mosaic Stadium.

The Saskatchewan Roughriders put together a complete three-phase effort on their way to a 40-27 win over the Calgary Stampeders, handing Calgary its first loss of the season.

"Total team effort, defence was amazing, special teams scored a touchdown for us and we had a good field position all night long, and then offensively, we were able to sustain some drives, moving forward we have to score touchdowns, but beating an undefeated team, a team that came into this game as the best team in the league, we'll take it anyway we can," said Riders quarterback Zach Collaros after the win.

The week started with questions about the direction of the Riders, who entered the game at 3-4 and released star receiver Duron Carter over their bye week.

A lot of those questions were answered by the Riders in a dominating performance against the top team in the CFL.

"We do things for a reason, we decided that was the direction that we were going in and whether or not that had anything tonight, I just know we had a really good week of preparation, the guys seemed extremely focused and if they bring that type of focus and attitude for the rest of the year, we're going to be in every football game," said Riders head coach Chris Jones after the win.

Jones did caution that it was only one win and they have a long road ahead of them for the rest of the season.

"This is one game on a long journey, but the good thing is that we get to face all these Western opponents face-to-face and we're a good football team, we've just stubbed our toe a few times and we've got to learn to win games," said Jones.

In a reversal from their meeting three weeks ago in which Calgary jumped out to a 24-0 lead in the first quarter, this time around, Saskatchewan took control early, moving in front 14-0 after the first quarter.

Riders kicker Brett Lauther opened the scoring with back-to-back field goals, but momentum really swung in the Riders' favour when defensive back Nick Marshall intercepted Calgary quarterback Bo Levi-Mitchell and returned it 67 yards for a touchdown.

The Stamps answered back with a quick 45-yard TD strike from Mitchell to DaVaris Daniels early in the second quarter.

The momentum only stayed with Calgary for a short time as Riders linebacker Sam Eguavoen blocked a Rob Maver punt on the Stampeders' next drive, scooped it up and scored to make it 21-6 for Saskatchewan.

Another Lauther field goal would put the Riders in front by 18 points heading into halftime.

On Calgary's opening drive in the second half, defensive end Charleston Hughes made his presence felt with a strip-sack of Mitchell. That big play was quickly led to a one-yard touchdown run by Marshall, giving him an offensive and defensive touchdown in the game.

Marshall played quarterback in college with the Auburn Tigers and Jones said that he brings a lot to the table for the Riders.

"He's a ball player, I could put him just about anywhere, you could put him at running back, you could put him at quarterback, you could put him at receiver, you could put him at any of our defensive back spots and he just knows how to play football," said Jones.

He added that Marshall pressured him to give him a chance on offence, "That's why we did it tonight, over the break he called me and he told me, 'You put me in there and I'll get a yard,' so that's why we did it," said Jones.

Marshall's second score made it 30-6 for the Riders.

Calgary responded with two touchdown passes from Mitchell, one for 32 yards to Kamar Jorden and a 29-yard strike to Juwan Brescacin.

Mitchell would pick up his fourth touchdown pass of the game, a 17-yard connection with Daniels, in the fourth quarter, but the Stampeders weren't able to move much closer as Lauther connected on three more field goals to finish off the win.

Lauther went 6-for-6 on field goal attempts in the win, making him 12-for-12 in the last three games.

Collaros kept the offence on the move throughout the game, going 25-of-34 for 270 yards. 

Jordan Williams-Lambert was his top target as he finished with ten catches for 152 yards in a breakout performance.

"He's an unbelievable hands catcher, he catches everything with his hands, he's a really hard worker and believes in me and I believe him and when he gets an opportunity, he makes the most of it," said Collaros.

While Mitchell finished 22-of-36 for 275 yards with four touchdowns, the Riders' defence was able to keep him off balance throughout the game, led by Hughes, who had two sacks to extend his league-leading total to 11.

Linebacker Matt Elam had two sacks as well, while Willie Jefferson got his hands on Mitchell once in the win.

"Our guys disturbing and moving him off his spot helped us win the football game," said Jones.

The Riders are now back to .500 on the year with three more West Division games on the horizon in the next three weeks.

"It's just satisfying to get a win, especially against a great football team like that," said Collaros.

"We know what we have in our locker room, we believe in each other, believe in the system here under Coach Jones and we know what we're capable of, so it’s another win for us and we get to continue down that path to where we want to go."

The Riders travel to Vancouver to face the B.C. Lions on Saturday.