The Chicago Bears must come from behind to win at Soldier Field as the Green Bay Packers hold a 13-7 lead at half time.
Jay Cutler capped an 80-yard drive with a short pass for Matt Forte to give the Bears a late lead in the first quarter.
Mason Crosby got the Packers going with a 33-yard field goal in the second quarter, before a moment of contention saw the visitors go ahead for the first time.
Aaron Rodgers was hit from behind by Julius Peppers, causing the ball to squirm loose. Jarrett Boykin retrieved it and, at the behest of the coaching staff, ran it into the endzone.
After a lengthy review, the officials determined that it had been fumbled and awarded the touchdown.
Crosby added three more points seconds before the break.