In Showdown of Defenses, Texans Outlast Bears CHICAGO - The rain started to fall long before kickoff and did not stop. The Soldier Field turf turned muddy, the wind gusted, and the usually bright lights of the lakefront skyline were muted through the mist. The Chicago Bears and the Houston Texans each came into Sunday night as a 7-1 team built on defense. They played a defensive game in defensive conditions, and over four sloppy, soggy and hard-hitting quarters, the Bears lost their quarterback, Jay Cutler, and the Texans" Arian Foster proved why he may be the N.F.L."s best running back as Houston emerged with a 13-6 win. "At our stadium, we're not used to all this," the former Bear Danieal Manning, who had an interception and forced fumble, said of the rain. The thing is we got heads up early. I said bring all the seven-stud cleats you can bring and let's go out there and play. Sunday's game - with the Texans, one of the A.F.C."s top teams, taking on the Bears, one of the N.F.C."s best - was billed as a Super Bowl preview. Adding to the anticipation was that it was the first time since 2007 that teams with one or fewer losses had met this late in the season. The Texans boasted the league's third-ranked defense, and the Bears were the N.F.L. leader in turnovers forced. Neither defense disappointed, but the Texans were just that much better. The conditions quickly combined with opportunistic defenses to turn the marquee matchup into a grind-it-out game. A slippery ball and defenders flying all over the field led to six first-half turnovers. Kellen Davis fumbled on the Bears" first play from scrimmage and Michael Bush fumbled to end their second drive. Cutler threw two first-half interceptions, and Texans quarterback Matt Schaub matched him. During one stretch in the first half, four consecutive possessions ended in turnovers. Cutler never got the chance to atone for his rough start, leaving the game with a concussion. Late in the first half, a scrambling Cutler was leveled on a helmet-to-helmet hit by linebacker Tim Dobbins. Cutler was flagged on the play for a forward pass across the line of scrimmage, and Dobbins was penalized for hitting Cutler above the shoulders. Cutler finished the drive but did not return for the second half. He finished the game 7 for 14 for 40 yards and 2 interceptions. "Whatever the symptoms are for a concussion, that's what he had," Bears Coach Lovie Smith said. I try not to be Dr. Smith. Foster was the game's lone offensive star, piling up 102 yards on 29 carries. The Texans" zone blocking schemes and misdirection runs opened holes against an aggressive Chicago defense that preaches getting all 11 players to the ball. "It was just one of those games you knew you're not going to have great yards per carry average," Foster said. It's going to be one of those that you need to have every now and then as a running back for your team, and Coach Kubiak trusted me and the offensive line to get it done when it's crunch time. Foster scored the game's only touchdown, making a diving catch on an out route for a 2-yard score. It capped a second-quarter drive of seven plays and 66 yards, one of the game's few sustained offensive possessions. Schaub was 14 for 26 for only 95 yards to go along with the touchdown and two interceptions. Little changed for the Chicago offense with the backup Jason Campbell taking over for Cutler. Robbie Gould kicked field goals of 51 and 24 yards but missed a 48-yard attempt early in the fourth quarter that would have cut the Texans" lead to 10-9. Shayne Graham added his second field goal of the game a few minutes later to stretch the Texans" lead to 13-6, and the Bears never threatened again. "It's tough when you sit on the sidelines," Campbell said. It's not like we were playing against the 31st-ranked defense. Despite their records, both teams talked this week of proving themselves and earning the mantle of "Super Bowl contender." For the Texans, it was their first prime-time test since a 42-24 loss in Week 6 to the Packers at home on Sunday night. Against the Bears, they passed the test, using the time-tested formula of running the ball and playing sound defense. The Bears" lone loss of the season was also to Green Bay, a 23-10 defeat on a Thursday night in Week 2 at Lambeau Field, where Cutler threw four interceptions. The Bears had reeled off six straight wins, but none against a team with a winning record. Super Bowl fever gripped Chicago, as the Bears" defense racked up turnovers and scored touchdowns at a record-setting rate during their winning streak - even as questions remained about a shaky offense. As the Bears, soaked and beaten, trudged off the field Sunday night, those questions became more apparent, but remained unanswered. The Bears" lone loss of the season was also to Green Bay, a 23-10 defeat in Week 2 at Lambeau Field, where Cutler threw four interceptions.