Instead, Chicago jumped right back into the playoff race.
McCown threw for a career-high four touchdowns, and the Bears scored on their first eight possessions to grab a share of the NFC North lead with a 45-28 victory over the Dallas Cowboys on a frigid Monday night.
The Bears (7-6) retired Hall of Famer Mike Ditka's number at halftime and pulled even with Detroit in the division race on a night when the game-time temperature was in single digits and the wind chill factor was below zero.
The loss left Dallas (7-6) a game behind Philadelphia in the NFC East and owner Jerry Jones calling for more aggressive play-calling on defence.
The bone-chilling conditions didn't stop McCown from throwing for 348 yards or keep the Bears from running away with a lopsided victory.
It was one they desperately needed after consecutive losses, and although Detroit holds the head-to-head sweep, the Bears are back in the thick of the playoff race.
"All we could do is try to beat the Dallas Cowboys," coach Marc Trestman said. "We kept it as simple as that. We didn't get into all the hypotheticals and all the things that go into winning or losing a game."
Alshon Jeffery's leaping catch between two defenders in the corner of the end zone in the closing seconds of the second quarter gave the Bears a 24-14 lead, and they continued to pour it on in the second half after a gut-wrenching overtime loss at Minnesota last week.
McCown, making his fourth straight start with Jay Cutler sidelined by a high left ankle sprain, became the first Bears quarterback to throw for 300 or more yards in three straight games. And for that, DeMarcus Ware blamed Dallas' defence.
"If you were back there quarterbacking and we played the way we played you probably would have five touchdowns," he said.
McCown, meanwhile, insisted he's still the backup. And Trestman said the plan with Cutler hasn't changed.
"We'll see where Jay is this week," he said. "He'll have to be released by the doctors and when Jay is ready to play, he'll be playing."
Brandon Marshall caught six passes for 100 yards, and Jeffery added 84 yards receiving after breaking his own team record the previous week with 249.
Matt Forte chipped in with 102 yards rushing and 73 receiving, and the Bears racked up 490 yards in all.
"Basically, we will have to make some adjustments in what we are doing defensively," Jones said. "What that usually means is taking more risks on defence. But if you're going to have the kind of match like we had tonight or certainly in New Orleans you have to take some risks. We have to double up and I'm sure that will be part of the plan on defence; more risks."
Tony Romo threw for three touchdowns but completed just 11 of 20 passes for 104 yards for Dallas. DeMarco Murray ran for 146 yards against the league's worst run defence, but the Cowboys were overmatched after winning two straight.
They also lost linebacker Sean Lee to another injury — this time a neck issue after making a tackle in the third quarter. He missed the previous two games with a hamstring problem.
"Certainly, it was a disappointing loss and the loss stings," coach Jason Garrett said. "The worst thing we can do is have a hangover after this loss."
The game-time temperature was 8 degrees with the wind chill at minus 9, but the freezing conditions did nothing to slow either team in the early going. Garrett said both teams handled it well.
Murray burned Chicago for 52 yards on six carries on the game's opening possession to set up a 2-yard scoring pass from Romo to Dez Bryant, but the Bears scored just about every time they got the ball.
After Bryant's TD, McCown tied it with a 4-yard pass to Earl Bennett and put Chicago ahead 14-7 early in the second quarter with a 7-yard scramble, leaping at the goal line and getting spun in midair.
Jason Witten tied it at 14 when he dragged Major Wright across the goal line on a 10-yard touchdown catch, but the Bears grabbed a three-point lead on Robbie Gould's 27-yard field goal with 1:33 remaining in the half.
Jeffery added to it with that neat catch after Dallas was forced to punt.
"I'm just trying to give him a chance to go up and make the play but not really put the ball in jeopardy, so to speak," McCown said. "My part was relative easy to the catch."
NOTES: The record low temperature for a Bears home game is 2 degrees against Green Bay on Dec. 22, 2008. The lowest wind chill was minus 15 against the Packers on Dec. 18, 1983. ... There was a moment of silence for Nelson Mandela before the game.
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