Stand-in quarterback Josh McCown starred for the Bears, throwing four touchdowns and running for one of his own, as the hosts dominated the Cowboys' beleaguered defence, making 497 yards and scoring on their first eight possessions.
The result leaves the Cowboys' qualification for the NFL playoffs hanging in the balance, with the Philadelphia Eagles now in control of the NFC East with just three games remaining, and Garrett has acknowledged that his side needed to bounce back from the defeat as quickly as possible.
"Certainly, it was a disappointing loss and the loss stings. The worst thing we can do is have a hangover after this loss," he told The AP.
The Cowboys will face the Green Bay Packers in their next match before back-to-back games against NFC East opponents, starting with the Washington Redskins and finishing the regular season with a potentially crucial fixture against the Eagles.