Quick postgame keys to the Vikings' 34-27 victory over the Steelers at Wembley Stadium.

The Cassel effect. Backup Matt Cassel got the start at quarterback because of Christian Ponder's rib injury and was efficient and turnover free (although he got lucky on a fumble). Greg Jennings was engaged for the first time this season, and scored two touchdowns off Cassel passes. And Adrian Peterson got some more room, and ran for 140 yards.

Scary defense. The Vikings defense did enough to win, but did anyone feel comfortable late as the Steelers seemed on the verge of a comeback? Only a big play by Everson Griffen, with a sack on the final stand, saved the day.

Just in time victory. Only one team has started 0-4 and made the playoffs, so this was a must-win for the Vikings.

It's worth noting that one of the first things Coach Leslie Frazier said after the game is Ponder is his starting quarterback. So ... let the QB controversy begin.

Here are the video highlights and final stats.

The Vikings have a bye this week before playing Carolina at home on Oct. 13.