MINNEAPOLIS — A small hop by the ball, a giant swing in momentum for the Vikings.

Three plays after Chicago recovered a dribbler of an onside kick to open the second half, Brian Robison reclaimed the football after forcing a fumble during a sack of Bears QB Jay Cutler.

The play started with Robison rushing the edge, beating the right tackle and spotting open space between him and Cutler.

"I saw him kind of pumping the ball and looking down field," Robison said. "In my head, I just thought, 'You've got to do something a little bit extra,' so I just tried to get the ball out of his hand, was able to do it, and as I went down, I saw the ball in front of me and just jumped on it.

"It almost just laid there for me, like, 'Here I am,' " Robison continued. "So I just got on it."

The Vikings turned a 10-point lead into a three-score game moments later when rookie Stefon Diggs recorded his second touchdown of the day (a 33-yard catch-and-run).

"It was definitely a momentum-changer," Vikings Head Coach Mike Zimmer said. "We're beating them pretty decently at that time and they get the onside kick and it's like, 'What the heck is going on here?' I think they had a couple first downs or something and for him to get that, that was big, very big.

Minnesota didn't loosen its grip the rest of the way in a 38-17 victory for its first sweep of the NFC North rivalry since 2007, Robison's rookie season and the first time that 10-year pro Chad Greenway played the Bears.

The linebacker said the Bears (5-9) could have executed a "pivotal change" without Robison's intervention.

"For them to get that onside was huge, so Brian's play was really big," Greenway said. "Chicago has given us so many problems over the years. It's just nice to beat them three times in a row. It hasn't been done in a long time."

Everyone on a Vikings defense that was without DT Linval Joseph, LB Anthony Barr and S Harrison Smith seemed to do a little extra without trying to do too much. The defense withstood an immediate challenge when Chicago's Deonte Thompson returned the opening kickoff 49 yards to midfield.

A holding penalty by center Hroniss Grasu, however, sent the Bears backward.

Tom Johnson, who started at defensive tackle while Sharrif Floyd slid to Joseph's role at nose tackle, forced a sack of Jay Cutler on second down to put the Bears in third-and-25 out of the gate.

The Vikings (9-5) recorded five sacks of Cutler on the day, including 1.5 by Danielle Hunter, 1.0 each by Johnson, Robison and Greenway, and the sack that Floyd split with Hunter. The Bears had only allowed 19 sacks in their first 13 games.

Greenway's 18th career sack included an assist from Cutler's right sleeve of his undershirt. Asked if he would have gotten Cutler down without the extra layer, Greenway said, "I honestly don't think so."

Greenway had "a good grip on it" and "tried to hang on because he's pretty strong and got the spin off."

"We got it going early on and kind of got them on their heels a little bit. Jay is one of those guys that you can't let get out of the pocket," Greenway added. "The time I had him on the sack, if he gets out of that, if he squirms out, he's going to make a play down the field. That's just the kind of ability he has with his arm strength and ability to look down the field and make good throws. It was important to contain him."

Earlier in the week, Floyd had joked about giving his toe to Joseph or trying to borrow 10 pounds from his teammate while filling the void.

"I can't wait for him to come back," Floyd said. "We know what his presence is like and how we feel with one unit. Today, we stood up as a team, as a defense, an offense and a special teams."

Floyd and Joseph worked well together.

"We're kind of similar in a way. He's bigger and stronger but we both use our speed and quickness to our advantage," Johnson said. "Chicago's got bigger guys, and we were able to capitalize on it, hit our gaps and make those guys play under and grab us.

"It was huge. We always say it starts up front," Johnson added. "If we have a good game, if we put pressure on the quarterback, then our DBs will be able to let loose and the quarterback is able to throw plays he normally wouldn't, and then good things start happening."

The longest pass play for the Bears gained 20 yards on a throw by Cutler to running back Matt Forte.

Zimmer said it was the best that the Vikings have rushed an opposing quarterback in "a while" and credited a combination of scheme and aggression.

"I've always said I want the offensive and defensive lines to kind of be the mentality of this organization, this football team," Zimmer said. "I thought we played a lot better today. They're probably tired of hearing me all week long, but I'm proud of them today."