As a result, they'll be finishing their season prior to the playoffs for only the third time since 2004.
Andy Dalton hit A.J. Green for a 21-yard pass in the final moments, setting up Josh Brown's 43-yard field goal with 4 seconds remaining. That lifted the Bengals over Pittsburgh 13-10 on Sunday, eliminating the Steelers from playoff contention after losing for the fifth time in their past six games.
"Obviously, not our day, and thus, not our year," Pittsburgh coach Mike Tomlin said. "Just not enough significant plays at the moments. Sounds like a broken record, but reality as we sit here."
While Cincinnati (9-6) assured itself a second consecutive playoff berth for the first time since 1981-82, the Steelers (7-8) will miss the postseason for the first time since 2009.
The Steelers, 12-4 each of the past two seasons, need a win next week at home against Cleveland to avoid only their second losing season since 1999. Pittsburgh entered Sunday in control of its fate, knowing that victories in its final two regular-season games would assure a playoff spot.
Instead, the Steelers failed to score during four consecutive fourth-quarter drives that would have given them the lead. Four times previously this season, Pittsburgh blew fourth-quarter leads in losses; two other times they were within one possession in the final quarter but did not score.
"It says you don't finish," safety Ryan Clark said. "You don't make the plays to win football games. You look at the years we went 12-4 and go to Super Bowls, we don't blow people out but these type of games, we find ways to make plays in the fourth quarter. That was the story all year."
Brown missed a 56-yarder earlier in the fourth quarter but earned a second chance when Reggie Nelson picked off Ben Roethlisberger and returned it to the Pittsburgh 46 with 14 seconds remaining.
The Bengals' only touchdown also was off a Roethlisberger interception—Leon Hall's 17-yard touchdown return in the first quarter.
Roethlisberger completed 14 of 28 passes for 220 yards with a touchdown, but his costly mistake in the final seconds ended Pittsburgh's playoff hopes. It marked the second straight week a Roethlisberger pick cost the Steelers: He threw an interception on the second play of overtime in last week's loss at Dallas.
"Disappointment, pain," Roethlisberger said of his feelings. "Letting a lot of people down, and it doesn't feel good."
Dalton found Green down the right sideline the play immediately following Nelson's interception, setting up Brown's winner. Green caught 10 passes for 116 yards and Dalton completed 24 of 41 for 278 yards and two interceptions for the Bengals (9-6), who snapped a five-game losing streak to Pittsburgh (7-8).
"It's a big win for the city of Cincinnati," Bengals coach Marvin Lewis said. "I know they just think that there's some complex (against Pittsburgh); there's no complex. You've just got to come play and win, and this group in there has very little history of anything (negative).
"We got some guys frustrated in there at times but we did a good job of hanging in there and not flinching and making big plays."
On a day Cincinnati's offense managed only 267 yards (including 14 rushing yards) and six points against the NFL's top-ranked defense, most of those big plays—aside from Green—came from the Bengals' defense.
The Bengals sacked Roethlisberger four times and allowed Pittsburgh to complete just 2 of 14 third downs. The Steelers were limited 280 yards and had three turnovers.
Pittsburgh did a decent job of keeping Dalton and Green in check, forcing a season-high three turnovers and making a season-high six sacks.
"Our defense was making the plays they needed to make to win the game," Steelers running back Isaac Redman said. "We just didn't help them out at all."
Still, the Steelers had one last chance when they took over with 44 seconds left. Roethlisberger rolled right and tried to hit Mike Wallace down the sideline. The ball sailed over Wallace's head and into the arms of Nelson, who had dropped an earlier pick.
It was just enough time for Dalton and Green to get together one last time and help Cincinnati take one more step away from its mediocre past.
"A lot of people talked about we hadn't been in in back to back seasons in 30 years; I don't worry about that stuff," Green said. "I've been here two years and we made the playoffs all two years. That's all we can control."
Steelers running back Rashard Mendenhall returned following a one-game suspension for conduct detrimental to the team, gaining a game-high 50 rushing yards on 11 carries.
NOTES: Cincinnati's 14 yards rushing were the second-fewest in franchise history. The Bengals had four yards rushing against the Baltimore Ravens in 2000 ... Pittsburgh TE Heath Miller left the game in the fourth quarter with a right knee injury and did not return ... Brown is now 8 of 9 since taking over for Nugent three weeks ago ... Five of Pittsburgh's eight losses this season have come by three points.