Down one with less than a minute left on the clock, the veteran quarterback appeared to forget which down he was on following an incomplete pass on fourth-and-six which turned the ball back over to Chicago to close out the game.
After the play, Brady raised four fingers to the officials in an apparent signal that he thought he still had a fourth down to work with.
It was a stark contrast to how the 43-year-old started the game.
He looked as clinical as ever in the first quarter, marching the Buccaneers out to a 10-0 lead.
However after a stuttering start, Chicago's offence finally got clicking in the second as the Bears found the end zone twice to take a one-point lead into the half.
Although a field goal put Tampa Bay back in front heading into the fourth, Bears quarterback Nick Foles did just enough to keep his side in the game as Chicago clinched the win with two late field goals.