THREE THINGS THAT NEED TO GO RIGHT ...
Running game needs to be dominant. The Ravens have to exploit the NFL's worst run defense, which is allowing 188.5 yards a game on the ground. This will allow the Ravens to control the clock and keep the ball away from Peyton Manning.
Matt Stover has to return to his old form. The Ravens can't afford another miss by Stover, who is 4-for-7 this season. Considering both teams have been involved in close games the past two weeks, this one could be another nail-biter.
... AND THREE THINGS THAT COULD GO WRONG
Manning takes advantage of a banged-up secondary. He is one of the few quarterbacks who have had consistent success against the Ravens (a career rating of 102.4). The Ravens will try to slow him down with a secondary that is without cornerback Samari Rolle and safety Dawan Landry.
Penalties kill the Ravens again. In two losses, the Ravens have been flagged 19 times for 163 yards. Two of them - Jarret Johnson's personal foul in Pittsburgh and Terrell Suggs' roughing-the-passer penalty against Tennessee - have been game-changing.
Joe Flacco turns the ball over in a key moment. The rookie quarterback has done an admirable job of limiting his mistakes in the first four games. But his third-quarter fumble in Pittsburgh and his fourth-quarter interception against Tennessee have come at critical times.