Paul Kruger, the rookie who spent most Sundays on the inactive list, delivered a game-turning interception in overtime to help serve up the winning field goal.
Mark Clayton, a former No. 1 draft pick who had just two catches in his past three games, had a breakout night with seven catches for a season-high 129 yards.
Clayton had two catches on the Ravens' first possession of the night and set up their second touchdown with a 54-yard play, for a 14-7 halftime lead.
"We talked about making big plays across the board," Clayton said. "We needed chunks of yards, and that played a big role in this game."
After Billy Cundiff was short on a hurried 56-yard field-goal attempt at the end of regulation, he hit the game-winning 29-yarder on the Ravens' second possession of overtime. With the Steelers at the 50-yard line and threatening to win the game, Kruger faked a blitz and dropped back into zone coverage.
"It was a designed blitz [from the right side] and I was the dropper," Kruger said. "I just happened to be at the right place at the right time."
Better than that, he rumbled 26 yards to the Steelers' 28 to set the table for a heavy dose of Ray Rice (four straight carries) and one kneel-down by Joe Flacco. From the 11, Cundiff drilled a perfect kick.
Kruger was playing in only his fourth NFL game since being drafted in the second round last April. Frustrated, he talked with coach John Harbaugh about his situation last week.
"We've had a few discussions about what I need to do to get on the field," Kruger said. "He said, 'Just keep fighting and work hard. When you're in the game, make the most of every opportunity.' "
Kruger played his most defensive snaps of the season against the Steelers and had two tackles in addition to the interception.
The Ravens anticipated Clayton's big night. They knew he would be man-to-man against cornerback William Gay, and Clayton won that battle all game.
Late in the second half, he beat Gay for a 54-yard completion from Flacco to the Pittsburgh 16. The drive ended with a fade to wide-out Derrick Mason for a 10-yard touchdown. It was Mason's first touchdown against Pittsburgh in 21 career games.
The Ravens also scored on their first possession of the game - a 2-yard run by Willis McGahee - after Clayton triggered the drive with catches of 20 and 12 yards. It was the first, first-half touchdown for the Ravens in their past seven games.