CHICAGO -- Sluggish for most of the afternoon, the Chicago Bears found their rhythm in time to make Marc Trestman a winner in his debut.

Jay Cutler passed to Brandon Marshall for the go-ahead touchdown in the fourth quarter, helping the Bears rally for a 24-21 victory over the sloppy Cincinnati Bengals on Sunday and giving Trestman a victory in his first game as an NFL head coach.

It wasn't quite the display the Bears were looking for after making some big changes in the offseason. But they made the most of a handful of big plays by Cutler and repeated mistakes by the Bengals.

"There were a lot of question marks," Cutler said. "How were we going to do on offense? Are the plays going to work? Are we going to be able to block them? Am I going to complete balls? So to go out there, it wasn't pretty, it wasn't perfect, we didn't think it was going to be. We made plays when we had to make plays."

Cutler threw for 242 yards behind a line with four new starters. Marshall had eight grabs for 104 yards, and the offense pulled it out after struggling most of the way.

The Bengals led by 11 in the third quarter and were up 21-17 early in the fourth when Tim Jennings jarred the ball from Mohamed Sanu following a reception and made the recovery.

Chicago took over at its 19 and got an 8-yard run from Matt Forte on fourth-and-inches at the Bengals 27 to keep the drive going. Cutler then found Marshall in the front corner of the end zone for a 19-yard touchdown with 7:58 remaining.

The Bears made big changes in the offseason, parting with star linebacker Brian Urlacher and hiring Trestman to replace the fired Lovie Smith with the idea that he could spark the offense and lead them to the playoffs after missing out five of the past six years.

Clearly, there's work to do. The offense seemed stuck most of the afternoon but came through in the end, with Cutler completing 21 of 33 passes. He also had two touchdowns to go with an interception.

Charles Tillman matched a career high with two interceptions, giving him 35 overall for Chicago. And Robbie Gould set a franchise record with a 58-yard field goal at the end of the first half following some questionable clock management by Cincinnati.

"I think it tested us and our backbone because it didn't go the way we wanted it to go, certainly, in the first half," said Trestman, who coached the CFL's Montreal Alouettes the past five seasons. "But the guys hung in there together, at halftime pulled themselves together and the team went out and played every play and were able to come out on top."