Coming off their bye week, the Steelers flew to INVESCO Field at Mile High for a Week 9 Monday night duel with the Denver Broncos.  Pittsburgh would trail in the first quarter as the Broncos closed out the game's opening drive with kicker Matt Prater booting a 40-yard field goal, yet the Steelers would answer in the second quarter as safety Tyrone Carter (who filled in for safety Ryan Clark) returned an interception 48&#160;yards for a touchdown. Denver would answer in the third quarter as quarterback Ben Roethlisberger was sacked by defensive end Kenny Peterson, which caused a fumble.  The ball would be picked up by linebacker Robert Ayers and returned 54&#160;yards for a touchdown.  Afterwards, Pittsburgh would answer with Roethlisberger completing a 3-yard touchdown pass to wide receiver Hines Ward.  In the fourth quarter, the Steelers would pull away as Roethlisberger connected with rookie wide receiver Mike Wallace on a 25-yard touchdown pass, followed completing a 3-yard touchdown pass to Ward.. How many touchdown passes did Ben Roethlisberger throw in the fourth quarter?