INDIANAPOLIS — Quarterback Joe Flacco connected with wide receiver Michael Pittman Jr. for a 10-yard touchdown pass with seven minutes to play, and defensive back Julian Blackmon had a critical interception as the Indianapolis Colts beat the Tennessee Titans, 20-17, at Nissan Stadium on Sunday afternoon. The win was the Colts' first against an AFC South opponent this season. Indianapolis is now 3-3 on the season. Flacco started at quarterback again for Anthony Richardson, who is battling an oblique injury he suffered in a week four win against Pittsburgh. Flacco finished Sunday's game 22-of-38 for 189 yards, two touchdowns and an interception. The Colts jumped out to an early lead with a 10-play, 70-yard drive on their first possession. The effort was capped by a 22-yard Flacco touchdown pass to wide receiver Josh Downs. The Colts' defense forced a three-and-out on Tennessee's first possession to give the ball right back to the offense, but Flacco threw an interception to safety Amani Hooker. The Titans cashed in on the takeaway as quarterback Will Levis found former Indiana Hoosier receiver Nick Westbrook-Ikhine for a 9-yard touchdown to tie the game at 7. The two teams swapped field goals to make it a 10-10 game at halftime. Tennessee ate up almost nine minutes of clock in the third quarter on a 14-play, 70-yard drive. Running back Tony Pollard broke free for a 23-yard touchdown run on 3rd-and-19 to put the Titans on top, 17-10. The Colts cut into the Tennessee lead with a 22-yard Matt Gay field goal on the first play of the fourth quarter. Pittman later secured a game-winning touchdown pass. The Titans needed a response when Levis was looking deep for wideout Calvin Ridley. Levis' pass was ultimately intercepted by Blackmon, who helped preserve the Colts' 20-17 lead. The Colts forced one more punt and stopped Tennessee on a final play to end the game. Richardson appeared to be on track to play this week, practicing three days with full participation on Thursday, but he was designated as the third quarterback on Sunday. Running back Jonathan Taylor missed his second straight game with an ankle injury, and Pittman Jr. played after news of a back injury that could have sent him to the injured reserve broke last week. Center Ryan Kelly left Sunday's game with a calf injury. The Colts return home next week to host the Miami Dolphins (2-3) at 1:00 p.m. on CBS4's broadcast partner, FOX59.