Maiocco’s observations: Guerendo and Kittle fuel the 49ers’ win over the Bears. Originally appeared on NBC Sports Bay Area

BOX score

The 49ers finally had some fun on Sunday.

After a few games in which the 49ers suffered decisive defeats, they turned the tables on the Chicago Bears at Levi’s Stadium.

The 49ers put on a dominant first-half performance to secure a 38-13 victory over the Bears and No. 1 draft pick Caleb Williams.

The Bears’ seventh straight loss was their first since coach Matt Eberflus was fired and replaced by interim coach Thomas Brown.

The 49ers (6-7) ended a three-game losing streak, including losses of 38-10 and 35-10 at Green Bay and Buffalo. According to NFL.com, San Francisco has a nine percent chance of making the NFC playoffs.

Very little has happened for the 49ers this season. Very little went wrong on Sunday.

Here are the key takeaways from the 49ers’ Week 14 game against the overwhelmed Bears:

Purdy eats up Bears’ D

Not all areas of the 49ers went well this season. And that includes quarterback Brock Purdy, who finished fourth in the NFL’s Most Valuable Player vote a year ago.

Purdy was back to his 2023 form on Sunday, and explosive play returned to the 49ers’ offense.

Purdy completed 20 of 25 pass attempts for 325 yards and two touchdowns with no interceptions and a passer rating of 145.5.

After recording just eight plays of 20 yards or more in the last three games, the 49ers scored eight big plays in the first half alone.

The 49ers scored on four of their first five possessions of the game, and Purdy made it look easy as he got the ball down the field and into the hands of his playmakers.

Purdy found wide receiver Jauan Jennings on touchdown passes of 7 and 16 yards.

Tight end George Kittle had a strong performance in the first half, throwing on all five targets for 138 yards. The All-Pro finished the win with 151 total receiving yards.

Purdy had passed for just 94 yards in the snow of Buffalo a week earlier. On Sunday alone, he completed 16 of 18 passes for 258 yards in the first half.

Guerendo, rusher and receiver

Rookie running back Isaac Guerendo started his first NFL game on Sunday. It was just his second start since completing his senior season as Indiana’s Mr. Football at Avon High, where he played wide receiver.

Guerendo gained 78 yards and scored two touchdowns on 15 rushing attempts. He added two catches for 50 yards against the Bears.

Guerendo left the game in the fourth quarter with a foot injury.

Guerendo’s only start in college – five seasons at Wisconsin and one at Louisville – came in the final game of his career, when the starter was eliminated from the Holiday Bowl.

Guerendo showed off his receiving skills from the first quarter of the game on Sunday. And it’s that well-rounded game that could allow him to move up the depth chart next season.

Guerendo came in due to injuries to Christian McCaffrey and Jordan Mason. Early in the game, he made a name for himself as a receiver, including a 27-yard pass to the 1-yard line. Guerendo hit it into the end zone on the next play, giving the 49ers a 14-0 lead.

Defense celebrates Williams

The total yards at halftime said it all: 49ers 319, Bears 4. It was the first game in the NFL this season in which there was a difference of at least 300 yards in the first half.

It was a tough day for Williams, a rookie who was selected with the top pick in the 2024 NFL Draft by USC. The 49ers’ pass rush utilized Williams in the first half, with all four sacks coming on third-down plays.

Leonard Floyd and Yetur Gross-Matos each recorded two sacks, while Maliek Collins registered a sack in the first half. Floyd passed Nick Bosa for the team lead in sacks. Bosa was forced to sit out his third straight game due to hip and oblique injuries.

In the first half, Williams completed six of nine passes for 27 yards but was sacked four times for minus-30 yards. Williams entered the game with a season-worst 49 sacks.

Williams lost a fumble in the second half, which rookie defensive tackle Evan Anderson recovered to equalize.

The 49ers made a notable change to their starting lineup when safety Talanoa Hufanga came off injured reserve and replaced Ji’Ayir Brown. Hufanga played alongside Malik Mustapha in the defensive backfield.