Shortly after they couldn't gain a yard with the Indianapolis goal line within reach, the Steelers suddenly couldn't be stopped.
Their rally from a 24-7, third-quarter deficit for 21 unanswered points produced a 28-24 victory that snapped a three-game losing streak and clinched the AFC North Division championship on Sunday afternoon at Heinz Field.
"I'm proud of the guys to finally get it done," quarterback Ben Roethlisberger said. "This wasn't our end goal."
The T-shirts handed out afterward read "Division Champions Won Not Done."
"We're excited about the hats and T-shirts," head coach Mike Tomlin said. "We've been waiting to put them on for a few weeks now."
The Steelers improved to 12-3 and scored 20 or more points for the first time in five games.
The Colts fell to 10-5.
The Steelers picked up 20 first downs and 260 total net yards while scoring 21 second-half points.
The Colts managed eight first downs, 148 total net yards and three points after halftime.
Game action photos from the Steelers' Week 16 game against the Indianapolis Colts at Heinz Field
Defensive end Stephon Tuitt summed up the locker room celebration as follows:
"It was exciting. It was overcoming. It was brotherhood."
The Steelers took their first lead midway through the fourth quarter with their third touchdown during a span of 10:38 in the second half.
Roethlisberger found wide receiver JuJu Smith-Schuster for a 25-yard touchdown, Roethlisberger's third touchdown pass of the game, with 7:38 left in regulation and kicker Matthew Wright's extra point put the Steelers ahead, 28-24. The touchdown pass capped a 10-play, 84-yard drive in 4:28.
Colts quarterback Philip Rivers was intercepted by cornerback Mike Hilton three plays later and the Steelers produced two first downs before punting the ball back to the Colts with 2:18 left in the fourth.
Indianapolis drove to the Steelers' 33-yard line on what would be its final possession, Rivers' fourth-and-8 pass for wide receiver Zach Pascal fell incomplete with 1:14 to play.
"We needed this game," Tuitt said. "We knuckled down. We made the plays we needed to make."
Outside linebacker T.J. Watt had two of the Steelers' five sacks (Tuitt, defensive tackle Cam Heyward and inside linebacker Avery Williamson had the other three).
The Colts had allowed 16 sacks in their first 14 games but were without starting offensive tackles Anthony Castonzo and Braden Smith.
"At them ed of the day I felt like we got after them pretty good," Watt said.
A 5-yard touchdown pass from Roethlisberger to tight end Eric Ebron and Wright's extra point drew the Steelers to within 24-21 with 14:52 left in the fourth. The five-play, 74-yard drive in 1:51 followed a second consecutive three-and-out series induced by the Steelers' defense.
The Steelers closed to within 10 at 24-14 on a 39-yard touchdown pass from Roethlisberger to wide receiver Diontae Johnson, who made a diving catch in the end zone, and Wright's extra point, with 3:16 left in the third quarter. The one-play drive followed a three-and-out on an Indianapolis possession that began at the Colts' 2-yard line after the Steelers turned the ball over on downs.
The Colts increased their 14-point halftime advantage to 24-7 on a 28-yard field goal by kicker Rodrigo Blankenship with 9:23 left in the third. A 10-play, 65-yard drive that opened the second half was stopped short of the end zone on a sack by Tuitt on third-and-3 from the Steelers' 7.
Indianapolis built a two-touchdown lead on a 42-yard scoring strike from Rivers to Pascal with 4:02 left in the second quarter. The possession began at the Steelers' 43 after a 22-yard punt return by running back Nyheim Hines and a 10-yard penalty for an illegal block on Steelers cornerback Justin Layne. Blankenship's extra point gave the visitors a 21-7 cushion.
The Steelers got on the scoreboard on a plunge by running back James Conner on third-and-goal from the Colts' 1 with 13:47 left in the second quarter. Wright's extra point tied the game at 7-7.
The touchdown was set up by a sack and forced fumble by Watt and cornerback Mike Hilton's fumble recovery and 14-yard return to the Indianapolis 3.
The Colts responded with a 12-play, 85-yard drive in 7:12 that re-established an Indianapolis lead at 14-7. Rivers was 4-for-5 passing for 64 yards and the Colts ran seven times for 21 yards on the march, which ended on a 1-yard burst by running back Jonathan Taylor. Blankenship converted for a seven-point Colts' advantage.
Indianapolis opened the scoring with a nine-play, 70-yard drive for a touchdown in 4:45 on the Colts' first possession. Rivers extended the drive when he hit wide receiver Michael Pitman Jr. for 26 yards on third-and-8 from the Colts' 32 and Taylor converted Indianapolis' second third down of the game when he darted into the end zone on third-and-goal from the 6. Blankenship's extra point gave Indianapolis a 7-0 lead with 9:48 left in the first quarter.