The upset was in large part due to a 95-yard fumble return for a touchdown by Bears safety Mike Brown, a play that provided essentially a 14-point swing at the end of the first half. The tide-turning runback also helped Smith make good on his promise, as he won four of his first five and six of his first eight contests against the Packers.

Fast forward to 2013 and Marc Trestman's first Packers-Bears game. Green Bay fans don't want or need a reminder, as a 5-2 Packers team riding a four-game winning streak saw everything change on that fateful Monday night when Shea McClellin sacked Aaron Rodgers and broke the MVP QB's left collarbone. The Bears walked away winners, 27-20, ending a six-game losing streak in the series that dated back to the start of the Packers' championship run in Week 17 of 2010.

However strangely, for a third straight time, Lambeau Field had served as a sort of twilight zone for a Chicago coach making his Packers-Bears debut. Rodgers ultimately got revenge eight weeks later on fourth-and-8 from the 48 at Soldier Field, but the damage, literally and figuratively, had been done.

It wasn't until 2015 that Green Bay finally flipped the script, in John Fox's first Packers-Bears tilt. In Week 1, as Sunday's clash is, but in Chicago, the Packers prevailed, 31-23.

How did they do it? Well, receiver James Jones returned from a short absence from Green Bay to catch two touchdown passes, and Clay Matthews had a crucial interception in the fourth quarter that helped put the game away.

So, if you combine the return to Green Bay of a previously departed player with an interception, does that mean Tramon Williams is the guy who has to make the difference for the Packers on Sunday night if the Packers? Is he the key to the Packers continuing their current four-game winning streak in the all-time series and boosting their overall won-loss advantage to three games?

Maybe so, but it also might just come down to this: