Minus two injured starters on defense for the first time this year -- starting safeties Mike Green and Chris Harris -- the Bears' defense began backpedaling on the second play from scrimmage and wound up getting plowed into the snow and mud by the Bus, Jerome Bettis.
The league's best defense coming into the game allowed a season's worst 190 yards rushing, including 101 yards on 17 carries by the 33-year-old Bettis. They yielded a season's worst 363 net yards of offense to a team that had lost three straight and was on the verge of being pushed right out of the playoff picture.
"When you play like that against a good football team, you usually get beat, it's as simple as that," Bears coach Lovie Smith said. "Of course, our strength is our defense and today we didn't play like we have all year.
"You can't let a good football team run the ball like that."
The Steelers' running game and 7-of-14 third-down conversions allowed led to a season's worst 37:19-22:41 time-of-possession disadvantage for the Bears.
"Yeah, we had a few guys missing, but that doesn't have anything to do with how we played," Smith said of his defense.
Bettis did the dirty work of finishing off the Bears' defense, gaining all but one of his yards in the second half. Running back Willie Parker and wide receiver Hines Ward started it by helping to stake Pittsburgh to a 7-0 lead on the Steelers' first possession. On Pittsburgh's second play from scrimmage, Parker caught a simple screen pass from quarterback Ben Roethlisberger (13-of-20, 173 yards passing) and went straight through the Bears' defense for 45 yards to the Bears' 22. Two plays later another screen pass, this time to Ward off of a fake end around to Ward, accounted for a 14-yard TD.
"It wasn't a good game for us," Bears middle linebacker Brian Urlacher said. "We didn't make any plays. We didn't do anything well. The whole game was ugly for us -- they played well
"I know I didn't tackle well, I missed a couple."
He wasn't alone. Pretty much the entire defense got caught grasping at air.
"To me, based on what I saw up there (in the coach's box), we just didn't tackle very well," defensive coordinator Ron Rivera said. "I think, at times, we were in positions to make plays and we didn't."
Bettis, in particular, gave the Bears this way.
"We were hitting him at the line of scrimmage and he was pounding it out for 2 or 3, a few more yards when they needed it," Rivera added.
Bettis scored the final two Steelers TDs, the first coming with 7:29 left in the second quarter for a 14-3 lead after another screen pass -- as well as a questionable coaching decision -- had burned the Bears' defense.
Smith opted to take an offensive pass interference penalty for third-and-13 at the Steelers' 35 rather than take fourth-and-one for a probable Pittsburgh punt from the Steelers' 47. In fact, Steelers coach Bill Cowher said he was going to punt on fourth-and-one.
"I did it for the chance that they would have gone for it," Smith explained. "I feel like it was a field position game today. I was trying to get field position. I feel like if we have someone in a third-and-long situation, I think we'll win most of those defensively."
They didn't. The Steelers ran yet another screen pass, this one to running back Verron Hayes. He barreled through the Bears' defense for 16 yards and five plays later the Bus plowed into the end zone for his specialty, the 1-yard TD run. A 5-yard TD run he added in the third quarter was his 86th career TD.
"He is a load," Johnson said. "When he can get going and come downhill, he's hard to take down. He's hard to tackle.
"He doesn't have all those touchdowns for no reason. He's just a tough kind of runner."
The defense did make several potentially big plays.
"We got four fumbles out, and we didn't recover any of the fumbles," Rivera complained.
The Bears' defense and Smith weren't the only ones having bad days. Kicker Robbie Gould made a 29-yard first-quarter field goal, but then missed the extra point wide left after Thomas Jones had scored the Bears' lone TD with 13:38 left in the game on a 1-yard run.
The extra point loomed large at the time because it left the Bears needing two TDs instead of a TD, two-point conversion and a field goal. But with the way the Steelers had begun to dominate the line of scrimmage, it later seemed irrelevant.
Quarterback Kyle Orton completed 17-of-35 for 207 yards, including a 43-yarder to Bernard Berrian to set up Jones' TD. He found Muhammad eight times for 91 yards, and Jones ran for 72 yards and a 5.1-yard average.
Yet they also had their problems. After the Steelers (8-5) led 7-0, the Bears marched downfield to first-and-goal at the 3-yard line. They wound up with fourth-and-11 after Jones got stuffed on first down for a yard loss and Orton was sacked for an 8-yard loss.
"On offense, it was a game of first-and-goal at the 3 and we came away with a field goal, a couple third-and-shorts that we didn't get," Orton said. "And then, I remember one third and eight or nine and we had a pretty good look for a slant (pass) and I was just off on the pass to Muhsin. We didn't convert on third down (3-of-13) and we didn't convert when we had first-and-goal from the 3."
So the Bears (9-4) returned to Chicago to face the Atlanta Falcons after their eighth straight road loss in December or January, still tied for the second seed in the NFC. But their defense looks a lot more vulnerable and their chances of winning the NFC North suddenly seem in jeopardy.
"We're still at the top," Smith said about the division. "But we need to win out. We came into this game thinking the same way, but we took a step back."