Mike Mitchell was "pretty sure" about what happened in Cincinnati in the immediate aftermath, but he wanted to be certain.

"I want to get in the film room," the Steelers' free safety insisted on Sunday after the Steelers had survived an 81-yard touchdown pass from quarterback Andy Dalton to wide receiver A.J. Green in what became a 42-21 victory over the Bengals. "Tomorrow can't get here soon enough."

The Bengals shocked the Steelers with that Dalton-to-Green home run ball on second-and-7 from the Cincinnati 19-yard line on the final play of the third quarter and grabbed a 21-17 led in the process.

Following is Mitchell's detailed description of what his further review confirmed:

"As a post-safety I'm responsible for everything 18 yards deep and deeper down the middle of the field. Now, on the route Cincinnati ran – hats off to (offensive coordinator) Hue Jackson, it was a great route – they ran a deep 'over' (route) by the No. 2 receiver (Mohamed Sanu), the guy in the slot. His 'over' came to about 17 yards up the field, which is just in the beginning of my zone.

"As I see that as a post-safety, not being on my job like I should be 100 percent, I see that 'over' and it makes me weave with it. While I weave you might think, 'Hey, that's not that bad.' But those 4 yards that I weave over are the 4 yards that I needed to get back to the post to have the right angle on A.J.'s ball that gets caught. If you look when I got to him, he had the angle to cut back on me. If I would have been 4 yards closer to him I probably would have been hitting him as he catches it."

The Bengals had a six-man protection (extra tackle Marshall Newhouse was eligible) and a four-man route on the play. Tight end Jermaine Gresham was wide left (covered by strong safety Troy Polamalu) and ran a sideline route to the Bengals' 30-yard line. Sanu was in the slot-right (covered by cornerback William Gay), ran his 'over' and was between the 35 and 40-yard lines when the ball was delivered.

Green was wide right (covered by cornerback Ike Taylor) and ran his deep post through initial one-handed resistance from Taylor at the snap. And running back Giovani Bernard (covered by linebacker Sean Spence) drifted out of the backfield to the 20-yard line.

The Steelers initially rushed five (outside linebackers Jason Worilds and Arthur Moats, defensive ends Stephon Tuitt and Cam Heyward, and nose tackle Steve McLendon). Linebacker Lawrence Timmons came on a delayed blitz and found an open lane to the quarterback but Dalton delivered the ball just prior to Timmons' arrival.

And by drifting with the Sanu route, Mitchell was unable to get to the Green route in time or at the proper angle. Green caught the ball at the Steelers' 36-yard line and cut back on Mitchell at the 30-yard line on the way to the end zone.

"So that was the correction: when I see the 'over' route in the front of my zone don't weave with it," Mitchell continued. "Stay square in your (back) pedal, keep coming straight back. The main threat, the best player on their team, is outside and he's the guy running the post. That's who you need to be alert for.

"I was really playing the situation. I wasn't expecting a 70-yard shot. I was thinking they'd think, 'Hey, let's try to get this route to the sticks, get the first down, keep the drive going.'

"They did a good job, drew up a play. We'd seen it before but where it was called on the field, that's more of a play that's called for midfield going in, those types of shot-plays. But they drew it up and they hit us. That was a tough lesson to learn but I learned it."

Mitchell's point was that the Bengals went deep from a spot on the field from which they hadn't shown a tendency to do so.

"The lesson is give them the underneath ball," Mitchell summarized. "We can come up and tackle that. That's a 20-yard gain, but we can tackle that. If we give up that post and I don't tackle that it's (81) yards.

"I felt horrible about it. I thought we were going to lose the game. That's a sickening feeling when you're in the post."