SAN FRANCISCO -- Colin Kaepernick won his starting debut so convincingly Monday night that a 49ers quarterback controversy could be afoot.
With Alex Smith sidelined by a week-old concussion, Kaepernick aggressively engineered a 20-point halftime lead in the 49ers' 32-7 rout of the Chicago Bears.
The 49ers (7-2-1) now must weigh benching the freshly minted Kaepernick in favor of Smith, assuming the eighth-year veteran eventually gets cleared from a Nov. 11 concussion.
"Usually I tend to go with the guy with the hot hand, and we've got two quarterbacks with hot hands," coach Jim Harbaugh said in not committing to either signal caller.
Kaepernick took a diplomatic approach to the brewing quandary, noting: "I don't think one game can be called a hot hand."
The 49ers' next game is a Sunday visit to the New Orleans Saints, who have won five of six since an 0-4 start. The Bears' second straight loss dropped them to 7-3.
Kaepernick completed 16 of 23 passes for 243 yards and two touchdowns, including a 10-of-12 start for 178 yards as the 49ers scored on their first four series for the 20-0 lead.
Harbaugh told his team Sunday night that Kaepernick would start, doing so ahead of Monday's news that Smith wasn't medically cleared by team doctors to return from his first concussion this season. Smith left the locker room without comment.
"There's not a big mystery here," Harbaugh insisted. "Alex still had symptoms on Sunday, and we were going to make the decision to go with Colin."
Complementing Kaepernick's dynamic outing was the 49ers defense, which outshined its more-heralded counterpart. Aldon Smith produced a career-high 5½ sacks to take the NFL lead with 15 overall.
While the Bears entered with a league-high 30 takeaways, they got none against the 49ers. Instead, the 49ers forced two turnovers, on interceptions by Tarell Brown and Dashon Goldson.
Known more for his "WildKap" rushing cameos this season, Kaepernick attacked the Bears with an array of on-target passes. His progress as a passer showed in the third quarter, when he calmly surveyed the end zone before finding Michael Crabtree for a 10-yard touchdown pass and 27-0 lead.
"I saw great pass protection, and it was a coolheaded decision by Colin," Harbaugh said. "Michael got separation and mirrored what Kap was doing, broke off his route, and they made a heck of a play."
Kaepernick's precision rivaled that of Smith's past two outings, when he completed 18 of 19 in a 24-3 win at Arizona and 7 of 8 before exiting a 24-24 tie with the St. Louis Rams.
Bears quarterback Jason Campbell, who started in place of a concussed Jay Cutler, ended the 49ers' shutout bid in the third quarter with a 13-yard touchdown pass to Brandon Marshall.
Any outside shot at a Bears comeback ended early in the fourth quarter when Aldon Smith's final sack yielded a safety.
Kaepernick's first drive as a starting quarterback produced points, albeit a 32-yard field goal from David Akers for a 3-0 lead to cap a nine-play, 68-yard drive. Kaepernick completed his first four attempts before overthrowing Vernon Davis in the end zone on third-and-1 from the Bears' 14.
Kaepernick's second series was a quick one, and it produced his first career touchdown pass -- a 3-yarder to Davis, who caught five passes for 72 yards in the first half. One play before that scoring strike, Kaepernick hit Kyle Williams in stride for a 57-yard completion on third down.
"We all knew what he could do," Williams said. "It was about getting an opportunity, and he was lights out tonight."
Bolstered by a 32-yard completion to Davis, the 49ers' third drive finished with a 14-yard touchdown run by Kendall Hunter for a 17-0 cushion. A 37-yard field goal by Akers made it 20-0 before the 49ers offense cooled down and punted on its final two possessions of the first half.
Adding to the 49ers' defensive dominance were Justin Smith's pocket pressure, Patrick Willis' all-around excellence and NaVorro Bowman's game-high 12 tackles.
The 49ers outgained the Bears 355 yards to 143. Frank Gore and Hunter combined for 105 rushing yards, and Davis finished with a team-high six catches for 83 yards.
"It sends out a message that we're for real," Davis said of the win.
Winning this NFC showdown also alerts everyone that the 49ers have two capable quarterbacks. Always one to buck conventional thinking, Harbaugh doesn't subscribe to the philosophy a starter can't lose a job to injury. Will that be the case with Smith?
"We'll make that determination as we go," Harbaugh said. "There's no rule."