The big plays for the Rams started on the game's first possession.
Facing third-and-13 at St. Louis' 42-yard line, Colts quarterback Andrew Luck was hit from behind by Rams defensive end Robert Quinn and lost the grip on the football. Quinn's defensive line bookend, Chris Long, scooped up the football at Indianapolis' 45-yard line and returned it untouched for the game's first score.
"I had my lion's share of mistakes," said Luck, who also threw three interceptions — including two in the end zone — and was sacked three times. "Some of those sacks are my fault. Those errors are my fault as well. Very good front four (in St. Louis), good football team and they beat us. Not much else to really say about it. They beat us fair and square in every which way they probably could."
The Colts' early deficit could have been worse, but St. Louis botched a handoff at Indianapolis' 5-yard line and lost possession on a fumble with 2:05 remaining in the first quarter.
It didn't take long for the Rams to find their footing and rebound.
Rookie running back Zac Stacy scored on a 1-yard run just 30 seconds into the second quarter, and then Austin began his scoring barrage.
His first touchdown came on a remarkable play. Indianapolis safety Sergio Brown hustled down the field on punt coverage, batting the ball backward to keep it out of the end zone. Austin picked it up on the rebound and sprinted 98 yards in the opposite direction for a touchdown.
"He has the chance to change games," St. Louis coach Jeff Fisher said, "and we're just going to keep working to get him the football."
The Rams did so successfully for their next two scores. Quarterback Kellen Clemens — playing because of a season-ending injury to starter Sam Bradford — finished 9-of-16 for 247 yards, but it was the two touchdown passes to Austin that broke the Colts' back.