A week after the Buffalo Bills knocked them out, the San Francisco 49ers had their own chance to bully.

Hosting a Chicago Bears team that had fired head coach Matt Eberflus nine days earlier, the 49ers took advantage of a confused opponent and won 38-13 in a game that quickly became one-sided.

The 49ers began with an explosive attack down the field. Running back Isaac Guerendo managed a 23-yard dump-off on one play, while quarterback Brock Purdy hit tight end George Kittle for 33 yards on the next. After just five plays, fullback Jauan Jennings cut to the left and scored the game’s first touchdown.

The Bears responded with a three-and-out.

The 49ers’ second touchdown drive went just as smoothly as the first. Guerendo and Kittle once again rattled Chicago’s defense despite the absence of 49ers playmakers like Christian McCaffrey, Brandon Aiyuk and Jordan Mason.

Were the Bears shaken by the organizational shakeup or perhaps they weren’t receiving as much defensive calls after the departure of their head coach and defensive lineman?

Jennings sputtered his defender out of rhythm to catch and run for a 16-yard touchdown with 12:20 left in the second quarter.

At halftime the game was even more one-sided when the lead looked 24-0.

Chicago’s meager four yards in the first half was the franchise’s smallest first-half performance since 1991, according to the broadcast; The 315-yard difference at halftime was the largest of any NFL game this season.

According to TruMedia Sports, the Bears’ 0.2 yards per play was the third-lowest first-half yardage average since 2012.

The Bears’ second-half improvement was too little, too late

The Bears switched to a more balanced attack in the second half after the pass-heavy product forced Williams to four sacks in the first half.

By reinstating the run, the Bears managed to mount better third-down attempts, and Chicago extended its drive for more than nine minutes in the third quarter.

And as Chicago reached the end zone, Williams dropped back on third-and-goal to hit fellow rookie Rome Odunze on an out route for a four-yard touchdown. Odunze caught an aerial pass in the back right corner of the end zone and made sure to get both feet in before falling out of bounds.

The two-point conversion attempt went through Cole Kmet’s arms, but Chicago’s defense forced a punt to keep the momentum … until Williams let a return pass slip out of his hands, 49ers coach Kyle Shanahan challenged the original rule on incomplete passes , which would be repealed. San Francisco defensive tackle Evan Anderson recovered the fumble.

The 49ers turned their turnover possession into another touchdown. And then: Williams found Odunze again for the second goal. But it was too little, too late.

The 49ers pulled their starters before the end of the game.

Bears safety Jonathan Owens, who is married to Simone Biles, intercepted 49ers backup Brandon Allen with 1:59 to play.

Purdy completed 20 of 25 pass attempts for 325 yards, two touchdowns and no errors. Kittle led all arms with 151 yards on just six targets. He caught all of his targets for more than 10 yards, including three for 30 yards.

Guerendo, who was in the lead back role after injuries to McCaffrey and Mason, managed 128 yards from scrimmage.

Williams completed 17 of 23 passes for 134 yards and two touchdowns.