SAN FRANCISCO — Strong-armed fill-in Colin Kaepernick made all the right throws, looking every bit a capable NFL No. 1 quarterback.

Kaepernick passed for 243 yards and two touchdowns in his first career start in place of the injured Alex Smith, and the San Francisco 49ers whipped the Chicago Bears 32-7 on Monday night in a highly touted NFC showdown that hardly lived up to the hype.

Kaepernick threw touchdown passes to Vernon Davis and Michael Crabtree, and Kendall Hunter ran for a 14-yard score as San Francisco (7-2-1) jumped out to a big lead by scoring on each of its first four possessions — with Aldon Smith wreaking havoc on the other side of the ball with 5½ sacks.

“I really wasn’t too nervous,” Kaepernick said. “I’ve had a lot of time in this offense. My teammates were really supportive.”

Jason Campbell, the other quarterback in this matchup of backups for two division leaders, threw a 13-yard touchdown pass to Brandon Marshall in the third quarter but was sacked five times and threw two interceptions in his first start since October 2011 for Oakland.

He faced fierce pressure all night, on the field for the Bears (7-3) as starter Jay Cutler recovers from a concussion suffered eight days earlier — just like Smith.

After Kaepernick’s stellar night on the big stage, there’s certain to be chatter of a quarterback controversy for the NFC West-leading Niners.

Aldon Smith took over the NFL sacks lead with 15, passing Denver’s Von Miller with 13, with the second-best total in franchise history behind Fred Dean’s six-sack day on Nov. 13, 1983, against New Orleans. Tarell Brown and Dashon Goldson each had an interception for San Francisco’s stingy defense, which shut down Campbell, Matt Forte and Co.

“It definitely wasn’t our best effort, by no means,” Campbell said.

Kaepernick, Aldon Smith and Hunter sure made general manager Trent Baalke look good for his selections from the 2011 draft class.