Write a question about the following article: Hoping to rebound from their road loss to the 49ers, the Steelers went home for a Week 16 interconference duel with the St. Louis Rams.  With Ben Roethlisberger recovering from his left high ankle sprain, backup quarterback Charlie Batch got the start. Pittsburgh delivered the game's opening punch in the first quarter with a 21-yard field goal from kicker Shaun Suisham.  The Steelers added onto their lead in the second quarter with a 10-yard touchdown run from rookie running back John Clay, which was his first career carry. Pittsburgh continued to increase their lead in the third quarter with a 49-yard field goal from Suisham.  Afterwards, the Steelers pulled away in the fourth quarter with a 1-yard touchdown run from running back Rashard Mendenhall, followed by a 2-yard touchdown run from running back Isaac Redman.

Question about the article:
What was the only scoring play of the first quarter?