Hoping to rebound from their road loss to the Ravens, the Broncos went home for a Week 9 Monday night duel with the defending Super Bowl champion Pittsburgh Steelers.  Denver would begin the first quarter with kicker Matt Prater making a 40-yard field goal, yet the Steelers responded in the second quarter with safety Tyrone Carter returning an interception 48 yards for a touchdown. The Broncos would regain the lead in the third quarter as defensive end Kenny Peterson forced a fumble during his sack of quarterback Ben Roethlisberger.  It allowed rookie linebacker Robert Ayers to return the fumble 54 yards for a touchdown.  However, Pittsburgh came right back with Roethlisberger's 3-yard touchdown pass to wide receiver Hines Ward.  Afterwards, the Steelers would pull away in the fourth quarter as Roethlisberger completed a 25-yard touchdown pass to wide receiver Mike Wallace and a 3-yard touchdown pass to Ward. Making an appearance during the game was American Nordic combined skier Johnny Spillane, a Steamboat Springs, Colorado native, who would go on to win three silver medals at the 2010 Winter Olympics in Vancouver three months later.
Question: How many defensive touchdowns were scored?
Answer: 2