A lightning-fast defense completely shut down the bumbling 49ers, and their offense marched up and down the field most of the day. By halftime, the Bears were on cruise control with a 41-0 lead, eventually winning 41-10 on a gorgeous sunny day at Soldier Field.
Clad in pumpkin-colored uniforms for the second year in a row against San Francisco, the Bears moved their unblemished record to 7-0, the organization's best start to a season since the 1985 team that won Super Bowl XX opened the year 12-0.
The Bears turned two fumble recoveries and a spectacular interception by Brian Urlacher into a quick 24-0 lead in the first quarter, setting a team record for first-quarter points in the process. They also matched a franchise record for points in a first half, set way back in 1948 against Washington, with that 41-0 lead.
Rex Grossman rebounded from the worst game of his career - four interceptions and two fumbles in a hard-to-believe 24-23 win at Arizona before the bye week - to complete 23 of 29 passes for 252 yards and three touchdowns in just three quarters of action. Backup Brian Griese took over at the start of the fourth period.
The 49ers (2-5) had four first-half turnovers, and the opportunistic Bears scored a touchdown off all four of them.
San Francisco averted a shutout in the fourth quarter on a 23-yard field goal by Joe Nedney - which was greeted by a chorus of boos from shutout-hungry Bears fans - and a 16-yard TD pass from Alex Smith to Antonio Bryant.
Urlacher's interception was a highlight reel play from last year's NFL Defensive Player of the Year and one of the more spectacular individual efforts in recent memory.
The former New Mexico Lobo got a paw in the throwing lane and batted Smith's pass into the air. As he was being driven to the ground by 49ers guard Justin Smiley, he speared the ball with one hand to come up with the pick.
Grossman lobbed a 5-yard TD pass to Muhsin Muhammad to make it 17-0 just six plays later.
Smith was stripped of the ball on the 49ers' next series, and Tommie Harris picked it up and ran to the San Francisco 13-yardline. That set up a 1-yard TD plunge by Cedric Benson and a 24-0 lead with just about a minute to go in the opening quarter.
The Bears had such a comfortable lead that they decided to go for it on fourth down from the shadows of the San Francisco goalline early in the second quarter. Grossman made a nice play-action fake and hit Desmond Clark for the score.
After the Bears took an early 3-0 lead, the 49ers Maurice Hicks fumbled the ensuing kickoff. Cameron Worrell recovered at the 15, leading to a 7-yard TD run by Thomas Jones. Smith and the 49ers were down 10-0 before their offense took a snap.
San Francisco entered the contest as the worst scoring defense in the league, giving up 32 points a game. But it was turnovers that did them in on Sunday as the Bears consistently had short fields to work with on offense. Drives started at the 15, 41 and 13, and they turned all three into touchdowns to take the big opening-quarter lead.
The 49ers coughed up the ball a fourth time late in the half when Bryant caught a fourth-down pass to pick up a first down but fumbled. Ricky Manning Jr. made the recovery.
Instead of running out the clock, the Bears capitalized again. Grossman found fullback Jason McKie for 26 yards down the right sideline to get the team in field goal range. Just one play later, Grossman's 27-yard TD pass to a wide-open Clark with 10 seconds left and completed a blink-of-an-eye 70-yard scoring drive in just 62 seconds.