Tyrann Mathieu didn't wait long to make an impact in his NFL debut.
With the game tied at 0-0, the St. Louis Rams were driving late in the first quarter. With the ball at the Rams 45-yard line, quarterback Sam Bradford found tight end Jared Cook streaking over the middle behind linebacker Karlos Dansby.
However, as Cook made his way towards the end zone, Mathieu, who was covering St. Louis wide receiver Tavon Austin, came hard in pursuit and managed to smack the football out and past the goal line.
Dansby recovered the football for a touchback, and the turnover led to an 80-yard scoring drive by Arizona, capped off by a four-yard touchdown pass from Carson Palmer to Larry Fitzgerald.
According to Arizona Sports 620's Paul Calvisi, as Fitzgerald came to the sideline he handed the touchdown ball to Mathieu and said, "That's all you, man. That's all you."
During his two years at LSU (2010-11), Mathieu had seven career forced fumbles.