PITTSBURGH — The games are dwindling to a precious few for Jerome Bettis, and the NFL's No. 5 career rusher is very aware that any game, any carry, any touchdown could be his last.

The occasional times he's carried recently he hasn't done much, averaging 1.3 yards per carry during a three-game losing steak that was threatening to end the Pittsburgh Steelers' playoff chances.

But as the NFL has learned, it's never wise to underestimate Bettis, who has revived his career a half-dozen times in recent seasons. Improbable or not, Bettis came up with another big game Sunday when the Steelers needed it most, ending their three-game losing streak and the Chicago Bears' eight-game winning streak with a 21-9 victory.

Bettis, who had gained as many as 50 yards only twice all season, took advantage of a muddy field and fast-falling snow to power his way to 101 yards and two touchdowns to help keep the Steelers in AFC playoff contention and tighten up the Bears' NFC North race.

Of all the surprises in this uneven Steelers season, this was one of the biggest: That Bettis, who previously had only 186 yards in 12 games, still had a 100-yard game left in him — and in one of their biggest games.

"He was classic Jerome Bettis," coach Bill Cowher said.

Even if the game wasn't.

The Bears (9-4) walked a thin line week after week during their longest winning streak since the Super Bowl Shuffle Bears of 1985 won 12 in a row, winning by scores such as 10-6, 13-3 and 13-10. With rookie quarterback Kyle Orton unable to generate much offense, they would grab a narrow lead and protect it with an aggressive defense that allowed the fewest points and yards in the league.

But such a system doesn't allow for even the slightest deviation, and the Steelers supplied that by driving for Ben Roethlisberger's 14-yard scoring pass to Hines Ward and a 7-0 lead on their opening possession.

Given the Bears' offensive inadequacies — they scored more than 20 points only once during the winning streak — such a deficit must have seemed huge. They never caught up, settling for a field goal after driving to the Steelers' 3 on their next possession and never doing much after that.

For a change, the Bears' defense wasn't perfect, and being average wasn't nearly good enough as the Steelers outrushed them 190-83 and outgained them 363-268.The Steelers (8-5) still trail the Bengals (10-3) by two games in the AFC North, but they picked up a game each on the Jaguars (9-4), Chiefs (8-5) and Chargers (8-5) in the race for the two AFC wild-card spots."The way we look at it, we can't afford to lose any games," Bettis said. "We put ourselves in this position by losing some games early in the season, then going on a three-game losing skid. We understand the position we've put ourselves in."A week after making four turnovers in a pivotal 38-31 loss to the Bengals, the Steelers fumbled four times but didn't lose any, exactly the kind of bounces the Bears got for weeks."We haven't played like that all year," Bears coach Lovie Smith said. "We didn't get it once. The defense didn't do the things we've done in the past."The Bears' first loss since Oct. 9 left them a game up in the NFC North over the Vikings (8-5), who play the Steelers at home next weekend. The Bears are home against Atlanta (7-5).Asked if the Vikings worried him, Orton said, "No, we're worried about getting better for next week. This was a tough game. This was a tough team. We won a bunch of games in a row and we beat some good football teams, but we're not going to win them all. You're not going to beat tough teams on the road all year."Even if that's exactly what the Steelers must do next week. Roethlisberger said they took a step forward by beating the Bears and ending a losing streak that they wouldn't have believed possible when they were 7-2.At a Saturday night meeting, coach Bill Cowher talked of the necessity of playing with desperation and regaining the confidence the Steelers somehow lost in losses to the Ravens, Colts and Bengals after winning 22 of 25 over two seasons."He said to have confidence in yourself," Roethlisberger said. "We have to get that back. We've lost that recently, and I think today we came out with a swagger that we can play this football team."Now, the Bears must be wondering if they can regain that mindset with only one home game and two division road games (Green Bay, Minnesota) remaining."We're trying to gain respect in the league and to do that, you've got to find a way to win tough games on the road like this," defensive end Adewale Ogunleye said.Notes:Steelers CB Deshea Townsend left with a concussion, but Cowher said no other problems were detected during tests. ... The Steelers are 20-6 in December and January regular-season games since 2000. ... Bettis' 61 career 100-yard games are the fifth most in NFL history. ... Ward's TD catch was set up by a 45-yard screen pass to Willie Parker and was the 51st of Ward's career, tying him with Lynn Swann for the second most in team history. ... The Steelers ran for 190 yards after being held to 251 yards rushing during their three-game losing streak.