Jacksonville's Blaine Gabbert connected with Cecil Shorts III on a 80-yard TD pass with 45 seconds left to beat the Colts 22-17 on Sunday.
The bizarre finish overshadowed Maurice Jones-Drew's 177-yard rushing performance.
Andrew Luck drove the Colts (1-2) 48 yards in five plays to set up Adam Vinatieri for a 37-yard field goal. That gave Indy a 17-16 lead and seemingly the victory with 56 seconds to go.
But on the next snap, Shorts got behind Colts safety Sergio Brown and Gabbert hit him in stride. Shorts sprinted free, diving into the end zone for the score.
Indianapolis had a chance to win it at the end, but Luck's pass into the end zone was broken up by Aaron Ross.
Jacksonville (1-2) got its first win under coach Mike Mularkey.