CHICAGO – For 3½ quarters Sunday, Vikings quarterback Teddy Bridgewater was playing his poorest game since the dreadful season opener, with his accuracy and, in one instance, his better judgment fading on third down.

The interception he threw just before halftime led to a touchdown for the Chicago Bears. He left six points on the field in the third quarter when he overthrew Mike Wallace as the speedy wideout was streaking down the right sideline. Another drive stalled when he winged a pass wide of open slot receiver Jarius Wright.

When Bridgewater walked out to the huddle with the Vikings trailing by seven with 4 minutes, 49 seconds remaining, he reminded himself to forget all about that.

"I told myself, 'Hit the reset button.' Whatever happened earlier in the game, it's in the past," Bridgewater said. "You have another turn to go down and get some points."

And when the Vikings really needed Bridgewater and their offense to deliver, they did it not just once, but twice as the Vikings stole a 23-20 victory at Soldier Field.

Blair Walsh kicked a 36-yard field goal as time expired for the Vikings' first victory in Chicago since 2007.

After Bears quarterback Jay Cutler gave the Bears a 20-13 lead late by scrambling for a 4-yard touchdown, Bridgewater led the Vikings on a seven-play, 84-yard game-tying drive.

Bridgewater took a sack on the first play of the drive, but he got the Vikings going with a 19-yard scramble on the following snap. Three completions and five plays later, Bridgewater found Stefon Diggs on third-and-4. Diggs took it from there. The electrifying rookie spun away from Bears cornerback Sherrick McManis and raced toward the pylon. He juked Bears cornerback Tracy Porter inside the 10-yard line then barreled into the end zone to finish of a 40-yard touchdown.

"When he came in to camp, we knew he was going to be special and make some plays for us," defensive end Brian Robison said. "And he showed it again today."

The Vikings defense, which had its hands full all day with the big-armed Cutler and his big-bodied wide receiver Alshon Jeffery, forced a three-and-out.

Bridgewater got the ball back with a minute remaining and chucked up a deep ball to wide receiver Charles Johnson, who has been relegated to a reserve role due to Diggs' emergence. Johnson jumped to make a 35-yard catch over two Chicago defenders.

After a 9-yard run by Adrian Peterson, Walsh kicked his 36-yarder and the jubilant Vikings stormed the field.

Bridgewater completed less than 50 percent of his throws and had 81 passing yards before the final two drives. He then completed six of his final seven attempts for 106 yards and a touchdown to help the Vikings improve to 5-2.

"I've been asked the question if this guy can, if he had to, lead us back to a victory. And I think you saw that today," coach Mike Zimmer said. "Teddy made some huge plays when he needed to, and that's Teddy. That's what he does."

Marcus Sherels gave the Vikings a 7-3 lead in the first quarter with a 65-yard punt return for a touchdown. The Vikings sealed the right edge for Sherels. Once he got to the sideline, only punter Pat O'Donnell was in his path, and he had no interest in avoiding the block of defensive end Danielle Hunter.

Just before halftime, with the Vikings up 10-3, Bridgewater locked on to Diggs and was intercepted by Bears cornerback Kyle Fuller at midfield. The Bears capitalized three plays later when Cutler lobbed a pass to the corner of the end zone to Jeffery, who outleaped cornerback Xavier Rhodes for the touchdown.

The Bears and Vikings traded field goals before Cutler scored to put the home team up, 20-13. The touchdown was set up for a fourth-and-1 conversion earlier in the drive when Cutler found Jeffery, who made the catch in front of Rhodes.

"We made way too many mistakes today, especially in the second half defensively," Zimmer said. "Simple things that shouldn't have happened."

But that set the stage for Bridgewater, Diggs and Johnson, who put Walsh in position to kick his third field goal of the day and his first walk-off game-winner in 23 months.

The Vikings, having won back-to-back games on the road against NFC North rivals, will ride a three-game winning streak into next weekend's home game against the St. Louis Rams.

"The guys did a great job of just digging deep," Bridgewater said. "They showed a lot of heart today."

Matt Vensel • matt.vensel@startribune.com