Torrey Smith's night began with a penalty that wiped out a long Baltimore touchdown.
It ended with a catch that gave the Ravens a season sweep of Pittsburgh.
Five plays after a sure scoring strike tipped off his fingers, the Baltimore rookie receiver held onto a 26-yard touchdown pass from Joe Flacco with 8 seconds remaining to lift the Ravens past the Steelers 23-20 on Sunday.
"For him to keep coming back to me, that meant a lot," Smith said.
Smith was flagged for holding on the game's first play, negating Ray Rice's 76-yard touchdown run. But he capped Baltimore's game-winning 92-yard drive by beating William Gay down the right sideline as the Ravens (6-2) snapped Pittsburgh's four-game winning streak.
Flacco finished with 300 yards passing and Baltimore swept the season series from the rival Steelers (6-3) for the first time since 2006.
"This Steelers-Ravens game is a game for men," Baltimore coach John Harbaugh said. "This is a game for big men. You've got to shine bright in this game if you want to win this game. And nobody shined brighter than Joe Flacco in this game."
The Steelers appeared to be in control after rallying from a 10-point deficit to take a 20-16 lead with less than 5 minutes to go when Ben Roethlisberger hit Mike Wallace for a 25-yard score.
Pittsburgh's defense held once and the Steelers moved in range for Shaun Suisham to attempt a 47-yard field goal that could have bumped their lead to seven.
A delay of game penalty, however, pushed Pittsburgh back five yards and the Steelers opted to punt.
"I accept responsibility for that," coach Mike Tomlin said. "There was some hesitation on my part."
Flacco, who fumbled midway through the fourth quarter to set up Roethlisberger's strike to Wallace, atoned during a brilliant 13-play drive.
He converted a fourth-and-1 at the Pittsburgh 49 with less than a minute to go to keep Baltimore's hopes alive, and Smith made up for a drop with the biggest play of his young career.
The Steelers got the ball back with 8 seconds left but Antonio Brown fumbled a lateral from Wallace and the Ravens poured onto the Heinz Field turf in celebration.
How excited were the Ravens? Harbaugh received a cut on his chin after being dropped by Baltimore general manager Ozzie Newsome.
It's hard to blame the Ravens for their giddiness, particularly after two of their last three seasons ended on the same field.
"We swept them, but don't be fooled - we'll see them again in January," Baltimore linebacker Terrell Suggs said. "This is the only team in the world that can play like we play and match us blow for blow."
With one dramatic drive, Baltimore ended Pittsburgh's surge and moved into a tie with Cincinnati atop the AFC North.
Flacco, who had come under fire from his teammates for inconsistent play, completed 28 of 47 passes and kept his head late after spending much of the second half trying to avoid Pittsburgh linebacker James Harrison.
The All-Pro sacked Flacco three times in his first game back after missing a month with a fractured orbital bone around his right eye, but Pittsburgh's pass rush disappeared on Baltimore's final drive. Given time to work, Flacco picked apart the NFL's top-ranked pass defense.
Gay couldn't stop Flacco from hitting Anquan Boldin on the crucial fourth down and then couldn't stay in front of Smith on the game-winning play.
"That was, on my part, the worst drive ever," Gay said.
And perhaps the finest moment of Flacco's career.
"You don't really have anything to lose," Flacco said. "You either score or you don't score. ... You take a couple of shots at the end zone and see what comes of it."
The Steelers trailed by 10 going into the fourth quarter but roared back behind Roethlisberger. Rashard Mendenhall scored from 1 yard out to pull Pittsburgh within 16-13 and Harrison swatted the ball out of Flacco's hand on Baltimore's next possession.
Gay recovered and Roethlisberger put the Steelers in front when he rolled right to avoid pressure and threw in the direction of Brown. Wallace streaked in front of his teammate for the score and Pittsburgh appeared to be on its way to avenging a 28-point loss to the Ravens in the season opener.
Roethlisberger finished with 330 yards passing to become the first Pittsburgh quarterback to top 300 in three consecutive games, but the Steelers' defense couldn't contain Flacco at the end.
Suggs picked off Roethlisberger's pass in the third quarter to preserve a 9-6 Baltimore lead. A dozen plays later, Rice darted in from 4 yards out to put the Ravens up 16-6.
The NFL's top-ranked defense couldn't make it hold up, though for once Flacco bailed the defense out in a relationship that's often been vice versa.
"In my eyes, to be totally honest with you, they're the defending AFC champs, so they're still the team to beat," Suggs said of the Steelers. "But if we're playing football throughout, we'll see them again in January. But they've got to come to our house."
NOTES: Steelers WR Hines Ward left in the second quarter with concussion-like symptoms after a helmet-to-helmet hit by Baltimore LB Ray Lewis. Tomlin called the injury "minor." ... Pittsburgh punter Jeremy Kapinos averaged 33.3 yards on three kicks a day after being signed to replace injured Dan Sepulveda, who is out for the season with a knee injury. ... Rice, who ran for more than 100 yards against the Steelers in the opener, was held to 43 yards on 18 carries. ... Smith finished with five receptions for 71 yards.