PITTSBURGH - The Pittsburgh Steelers were down by 10 points, and down to their fourth and last running back. Somehow, they found an offense that was missing for most of three quarters and a way to win a game that easily could have been lost.

Jeff Reed kicked a 46-yard field goal in overtime and the Steelers withstood two season-ending injuries to key players and a bad first half to outlast the Ravens 23-20 on Monday night.

Reed’s third field goal — and his seventh career game-winner — ended a back-and-forth game in which the Steelers (3-1) were down 13-3 late in the third quarter, rallied but couldn’t hold a seven-point lead, then won despite being without their top three running backs.

“We lost a lot of guys,” quarterback Ben Roethlisberger said. “I was more emotional, more vocal than I’ve ever been at halftime. I screamed at our offense. We were terrible in the first half. Not that we were great in the second half, but we bounced back.”

The Steelers managed to win the game, but lost first-round draft pick Rashard Mendenhall (fractured left shoulder) and right guard Kendall Simmons (right Achilles) for the season. Both will be placed on injured reserve, coach Mike Tomlin said.

“It is only devastating if you allow it to be,” Tomlin said.

The Ravens (2-1), losing for the seventh time in their last eight games in Pittsburgh and falling out of the AFC North lead, won the important overtime coin toss but were backed up by two penalties and a sack and Sam Koch had to punt out of the end zone.

Then, on third-and-8, Roethlisberger found fourth-string running back Mewelde Moore — playing only because of the injuries — on a key 24-yard swing pass for a first down at the Ravens’ 31. On third-and-14, Moore made a 7-yard catch to the 28 to give Reed the extra yardage he needed to make it.

“That was important — a 46-yarder there isn’t a given, and a 53-yarder isn’t easy,” Reed said. “I get too much credit. My foot won it, but that’s what I’m supposed to do in that situation.”

Moore said, “Coach Tomlin told me when I came here I’d be his minute man, that I had to be ready on a minute’s notice. Everything he said held true.”

Before that, the Steelers turned a 13-3 deficit into a 17-13 lead by scoring two touchdowns in a 15-second span in the third quarter and Reed added a 19-yard field goal, only to have Baltimore rookie quarterback Joe Flacco hit Derrick Mason for 35 yards ahead of Le’Ron McClain’s 2-yard TD run that tied it at 20 with 4:02 remaining.

Jim Rogash / Getty Images The Week in Sports Pictures The nation grieved for those hurt, killed and affected by the Boston Marathon bombings. After one of the suspects was caught on Friday — following a day-long lockdown and manhunt — sports returned to Boston over the weekend.

The Steelers, booed by their own fans while held without a touchdown for eight quarters since the second period of a 10-6 win in Cleveland on Sept. 14, finally awoke late in the third by going to a no-huddle offense with Roethlisberger lined up in a shotgun formation.

They resorted to the no-huddle almost by necessity, with running back Mendenhall out and Willie Parker (knee) not in uniform. They would also lose third-string running back Carey Davis (sprained ankle).

“We’re resilient,” Steelers receiver Hines Ward said. “There was no finger-pointing when we fell behind. We stayed together. I can’t say enough about that group of running backs.”

With only one first down since the first quarter, the Steelers got a second when Baltimore’s Jarret Johnson unwisely drew a personal foul penalty for an out-of-bounds hit following Nate Washington’s 8-yard run. With his best field position since the first quarter, Roethlisberger — sacked and harassed by Baltimore’s defense most of the game — found Santonio Holmes for a 38-yard touchdown pass three plays later on a third-and-4. Roethlisberger was 14-of-24 for 191 yards and was sacked three times.