Because of the frequency of how quickly the rematch is upon is, the keys really haven't changed, so I'll just kind of summarize the ones that don't change, and introduce one or two new ones.
For instance, I don't think I need to bring up that Adrian Peterson is still really really really good and the entire basis of the Vikings' offense, with Christian Ponder continuing his inexorable slide into the waste pool that is bad quarterbacking, particularly with his top passing weapon in Percy Harvin about to miss yet another game. Nor do I need to mention that Jared Allen is still the main man to watch for on the Vikings' defense, having finally broken his three-game sackless streak with a pair in the loss to the Packers last week.
But as far as the remainder...
3) Continue to Throw to Brandon Marshall as the Focal Point of the Offense
At this point, the offense entirely runs on Brandon Marshall as his ability to get open against inferior defensive backs. But against the Vikings two weeks ago, Marshall caught 12 balls and didn't break 100 yards. It was the "Let Marshall make short catches, but don't permit him anything more than that" strategy, and it was actually effective. Continue to get Marshall involved, but he has to make bigger plays than that.
4) Create a Second Consistent Target
Is that Forte out of the slot or split wide? Is it Alshon Jeffery, returning from his knee scope? Can Devin Hester make a couple plays? Can the Bears have a tight end that doesn't drop balls and makes catches-- okay, we're looking for keys, not wishful thinkings. But the Bears have lacked a second, consistent receiving threat all season, and sooner or later, one needs to show up.
5) Create a Short Field and Convert
The Bears only came away with one takeaway against Marshawn Lynch, which created a short field, but the Bears didn't capitalize on it. With an offense that's only really come through when aided by an opportune penalty by the defense on third down, 80-yard drives just don't come that easily. Christian Ponder's thrown three picks in the last two games and 11 since week 5, with at least one interception in all games since then except for the Vikings' second matchup against Detroit. If the Bears pick Christian Ponder off without their top interceptor in Tim Jennings, they need to convert.
6) Stop, Stop Rudolph.
No Christmas puns? Fine. How about we just say that since Harvin's injury, Kyle Rudolph's become a very consistent performer for the Vikings. We talked about how he had a pretty good game against the Bears two weeks ago, but over the last three games, that was the game he caught the fewest balls in. Over the last three, he's caught 18 for 170 yards and three touchdowns, which for a tight end is pretty good, unless your name is Jason Witten or Tony Gonzalez, then it's a disappointment. Either way, the Bears can't leave Rudolph on those flat routes that he worked really well two weeks ago.