Answer based on context:

Hoping to rebound from their road loss to the Panthers, the 49ers went home for a Week 14 duel with the Minnesota Vikings. In the first quarter, the Niners trailed early as Vikings DT Kevin Williams returned an interception 18 yards for a touchdown, while kicker Ryan Longwell managed to get a 48-yard field goal. In the second quarter, Minnesota sealed the win early as QB Tarvaris Jackson completed a 19-yard TD pass to WR Robert Ferguson, Longwell nailing a 46-yard field goal, and RB Chester Taylor getting an 84-yard TD run. In the third quarter, San Francisco would get their only score of the game as QB Shaun Hill completed a 5-yard TD pass to WR Arnaz Battle. With the loss, the 49ers fell to 3-10. The only positive from the game was that the Niners held rookie RB phenom Adrian Peterson to just 3 rushing yards on 14 carries. Starting QB Trent Dilfer (7/19 for 45 yards and 1 interception) left the game in the second quarter with a head injury.

How many yards per completed pass did Trent Dilfer average during this game?
6.42