CHICAGO – All week, the Vikings heard about how offenses had taken a torch to the Chicago Bears defense — which is not exactly the second coming of the Monsters of the Midway — in recent weeks.

One reporter even asked if the Vikings were salivating at the thought of playing a team that had allowed 50-plus points in back-to-back games, the first time since 1923 that it happened in the league.

But the Vikings figured that the Bears defenders would be ticked off after their embarrassing play made them a punchline everywhere from the four-letter sports network to social media, and they knew that a similar offensive explosion would be far from a given for them Sunday.

And it was. The Vikings, after scoring on their first two possessions to take a 10-0 lead, saw their offense grind to a halt against the NFL's 31st-ranked defense in a 21-13 loss at Soldier Field, where they still haven't won since 2007.

"We knew coming into this game that Chicago was a defense full of pride," quarterback Teddy Bridgewater said. "They have a bunch of guys on that defense that have established themselves in this league."

Collectively, the Bears have established themselves as one of the league's leakiest defenses this season, allowing 29 points per game entering Sunday and 133 total in their last three games. But the Vikings' inefficient offensive performance seemingly had less to do with what the Bears were doing than it did with what they themselves weren't doing.

"Nothing special," said Chicago defensive end Jared Allen, who recorded a sack in his first game against his former team.

The Vikings' rookie quarterback had 56 passing yards through three quarters. Their leading rusher Sunday was a backup safety. Their top three targets in the passing game — including tight end Kyle Rudolph, who was shut out in his return from sports hernia surgery — combined for three catches. Starting running back Jerick McKinnon had 12 rushing yards after the first possession.

And as a result, the Vikings as a team went nearly three full quarters without stringing a pair of first downs together while the Bears reeled off 21 unanswered points.

Still, despite being outgained 468 yards to 243 and outpossessed by more than 17 minutes, the Vikings had a chance to tie the score late. Trailing 21-13 when they got the ball back with two minutes left, Bridgewater completed three consecutive passes, moving the Vikings to the Bears' 29.

But on second-and-3, Bridgewater tried to float a pass to Charles Johnson and was picked off in the end zone by Bears safety Ryan Mundy. The ill-advised throw had little chance of being completed, but the odds would have been slightly better had Johnson, who led the Vikings with six catches for 87 yards, made an effort to go up for the catch.

"[Bridgewater] was not as good today as [he] has been," coach Mike Zimmer said. "I thought in the fourth quarter he did better and then the … end of the ballgame was not a good situation. But I think he was up and down today."

Bridgewater continues to be inconsistent, which is to be expected of a rookie. The Vikings offense is averaging 14 points per game since Bridgewater's impressive starting debut against the Atlanta Falcons in Week 4. Sunday was the team's fourth loss when allowing their opponents to score 21 points or fewer.

Bridgewater and the offense appeared headed in the right direction when they scored three second-half touchdowns to beat Washington on Nov. 2. But the offense was unable to find a similar rhythm Sunday after their bye week.

"Part of it had to do with the defense," Zimmer said. "We didn't allow them to get into any kind of rhythm whatsoever throughout the day because we kept letting them convert on drives, so I think it's hard offensively when you're sitting on the sideline for a long time."

The Vikings did not sack Bears quarterback Jay Cutler and couldn't contend with the size of the Bears receivers, who routinely boxed out their defensive backs — often cornerback Josh Robinson — for first downs and touchdowns. Chicago converted on 10 of 17 third-down plays and two of three on fourth down. The Bears had 24 first downs compared to the Vikings' 10 and ran 28 more plays than the visitors.

The Vikings intercepted Cutler twice, including the first pick of cornerback Xavier Rhodes' career, but they could not convert any of them into points, not even when Harrison Smith returned one interception to the Bears 2; kicker Blair Walsh pushed his 38-yard attempt wide right.

The loss dropped the Vikings to 4-6, and into the NFC North basement. They play their next three games at TCF Bank Stadium, and they will likely need to win all of them to keep any hope at a playoff push alive.

And to do that, Bridgewater and the offense need to find its groove and find it quickly.

"We'll want to play better than we did today, that's for sure," Zimmer said.

Matt Vensel • matt.vensel@startribune.com