PITTSBURGH (AP) -- The field was soft and muddy and the snow was falling heavily on one of those nasty-weather days most NFL offensive players despise. To Jerome Bettis, the conditions were next to perfect.
Bettis, the NFL's No. 5 career rusher but a forgotten man much of the season, plowed through the muck and snow for two touchdowns and 101 yards as the Pittsburgh Steelers beat Chicago 21-9 on Sunday to end the Bears' eight-game winning streak.
A season-long lack of offense finally caught up to the Bears (9-4) as their normally exceptional defense was merely average, failing to generate any turnovers despite a day seemingly made for mistakes. Instead, it was made for the 260-pound Bettis, a power
runner who doesn't need snow tires when the temperatures fall and the going gets rough.
"He's a mudder," wide receiver Hines Ward said. "Those were great field conditions for him. People think he's down and out and he had a game like he had today."
Bettis, held to 22 yards on 14 carries in his previous two games, had his first 100-yard game in the regular season since getting 117 on Dec. 26 against Baltimore. Bettis' previous season high was 56 yards against Cincinnati on Oct. 23, and he had only 186 yards in Pittsburgh's first 12 games.
Before Bettis got rolling, Ben Roethlisberger -- all but ignoring the deep pass because of his bad thumb and the bad weather -- threw a 14-yard touchdown pass to Ward on Pittsburgh's first drive after hitting Willie Parker for 45 yards, both on screen passes.
After that, the Steelers (8-5) played a nearly error-free game to end a three-game losing streak, stay alive in the AFC playoff race and cut the Bears' lead over Minnesota (8-5) to one game in the NFC North.
Bettis had 60 career 100-yard games before Sunday, but even he didn't know if had another left in him.
"Absolutely not. My role is to come in and spell Willie Parker," Bettis said. "But this game was set up for me with the weather and the conditions."
At one point, Ward walked up to Bettis and reminded him that nobody runs in bad weather like he does.
"We were desperate," Ward said. "It's a one-game season every week for us. We've got to play like it's the playoffs, because we don't have a lot of room for error."
The Steelers' three touchdowns matched a season high against the Bears, and their 21 points were the most against Chicago since a 24-9 loss to Cincinnati on Sept. 25. The Steelers outgained the Bears 363-268 and outrushed them 190-83 after being held below 100 yards rushing during each game of the three-game losing streak.
"We're a lot better defense than we were out there," coach Lovie Smith said. "It was a bad day for the Bears."
With the Bears' defense allowing only 68 points during their longest winning streak since the 1985 Super Bowl championship team won 12 in a row, rookie quarterback Kyle Orton kept winning -- even while fumbling 11 times and throwing 13 interceptions.
But when the Bears (9-4) finally needed him to bring them from behind, Orton (17-of-35, 207 yards) couldn't do it -- or come close. Still, Smith never considered pulling him for Rex Grossman, who is back after breaking an ankle during the preseason.
The Bears drove to the Steelers' 3 following Ward's third touchdown catch in two games, but Orton was sacked for an 8-yard loss on second-and-goal and threw incomplete on third down. That forced them to settle for Robbie Gould's 29-yard field goal and a 7-3 deficit.
"I'm not happy with that one," Orton said. "We've got to get better."
Six Bears possessions and punts later, the Steelers led 21-3 after Bettis scored on runs of 1 yard midway through the second quarter and 5 yards in the third quarter.
Roethlisberger (13-of-20 for 173 yards, no interceptions) threw almost no high-risk passes a week after having a career-high three interceptions in a damaging 38-31 loss to Cincinnati that left the Bengals in control of the AFC North. The Bengals (10-3) stayed two games up by beating Cleveland 23-20 on Sunday.
"We saw something in the Bears defense that made us think we could run the ball against them," Roethlisberger said. "We wanted to get back to what the Pittsburgh Steelers are supposed to do."
In a four-way race for the two AFC wild-card spots, the Steelers trail the Jaguars (9-4) by a game and are tied with the Chiefs (8-5) and Chargers (8-5). But the Steelers have the worst conference record (6-5) of the four, a problem if there are any
The Bears played without both starting safeties, Chris Harris (knee) and Mike Brown (calf). ... Thomas Jones, the Bears' 1,000-yard rusher, had 72 yards but hasn't had a 100-yard game in seven games. ... Bettis' 100-yard game was only the Steelers' fourth of the season; they had 11 while going 15-1 last season. ... No NFL team has missed the playoffs after going 15-1 the previous season.