INDIANAPOLIS - Forget the first 55 minutes, when the Pittsburgh Steelers dominated the Indianapolis Colts. And no one will remember much how they scored all the points.

What they’ll be talking about in Pittsburgh for years to come is those last five, thrilling minutes, a wild finish made of missed opportunities, gut-wrenching twists and one unimaginable, tide-turning play after another.

The Steelers won their sixth straight game Sunday, 21-18 over the Colts, becoming the first sixth seed to advance to a conference championship game. When the Steelers (13-5) catch their breath, they’ll head to Denver, with the winner next Sunday representing the AFC in the Super Bowl.

“It was a unique game. It ranks up there. It was crazy,” Jerome Bettis said.

“It went from an all-time high to an all-time low back to an all-time high,” Hines Ward added.

In a matter of minutes, too — holding the deafening crowd spellbound.

Pittsburgh spent three quarters building a 21-10 lead with a pass-first game plan that could’ve come straight from Indy.

Then things got wacky:

All-Pro safety Troy Polamalu made a diving interception of Peyton Manning at the Pittsburgh 48 with 5:26 remaining. He got up to run and fumbled the ball, but recovered — only to have it mysteriously overturned by referee Pete Morelli.

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Peyton Manning capitalized with passes of 20 yards to Marvin Harrison and 24 to Reggie Wayne before a 3-yard touchdown run by Edgerrin James and a 2-point conversion pass to Wayne.

Pittsburgh was forced to punt, but with 1:20 remaining, the befuddled Manning was sacked for the fifth time, on fourth down at his 2.

Game over, right?

Not on your life. The surehanded Bettis fumbled when popped by linebacker Gary Brackett. Nick Harper, whose knee was cut with a knife Saturday in an apparent domestic dispute with his wife, grabbed the ball and headed toward a highly improbable winning touchdown.

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But Steelers quarterback Ben Roethlisberger, brilliant all game with his arm and head, tumbled, reached out a hand and made a saving tackle at the Indy 42.

“Once in a blue moon, Jerome fumbles,” Roethlisberger said. “Once in a blue moon, I make a tackle. They just happened to be in the same game.”

Two passes got the ball to the Pittsburgh 27, and Vanderjagt lined up for a 46-yard field goal to send it to overtime.

Wide right.

Vanderjagt slammed his helmet to the turf, obviously forgetting how fortunate he was to have had the chance.

“It’s extreme disbelief,” Vanderjagt said. “From the Polamalu interception reversal to Jerome’s fumble, everything seemed to be lined up in our favor. I guess the Lord forgot about the football team.”