"No. 1, most importantly, we got a win," Krenzel said. "It was a great team effort.
"Personally, I think I did some really good things out there, threw some nice passes."
Krenzel threw a touchdown bomb on his first pass of the game and went 13-of-25 for 168 yards in a game that was downright ugly at times between two of the NFL's worst teams.
The Bears (2-5) supplied the rookie with plenty of help.
So did the 49ers (1-6).
Anthony Thomas produced his first big rushing game of the year in relief of injured Thomas Jones, going for 98 yards on 25 carries as the Bears had 120 yards as a team. The Bears' defense enjoyed its best run-stopping effort of the season, holding the Niners to 62 rushing yards. And special teams had key returns by Jerry Azumah and R.W. McQuarters as well as Paul Edinger field goals of 51, 45 and 27 yards.
"It's been a long time since we beat Green Bay. We forgot the feeling of how good it really does feel to get a win," said Bears coach Lovie Smith, whose team ended a four-game losing streak. "Craig Krenzel stepping in for his first game, national TV, I think he did a good job of managing the game.
"Getting off to the good start with the long touchdown pass really helped a lot. That's what we need our quarterback to do is get us into the right spot."
The 49ers started second-year quarterback Ken Dorsey in place of starter Tim Rattay due to a forearm injury. The former Miami Hurricane played much of the night like he was actually the one with the forearm injury.
Dorsey went 16-of-36 for 122 yards and was hounded into three sacks.
Dorsey threw an interception to Bears rookie Nate Vasher at the Bears' 29 with San Francisco driving for the tying or go-ahead points with four minutes left in the game. Vasher returned it 71 yards for a clinching touchdown and a 23-13 Bears lead with 3:52 to play.
A replay challenge by 49ers coach Dennis Erickson contended Vasher had been touched down by 49ers receiver Brandon Lloyd before getting up and taking it back for the score. However, officials ruled Vasher had bobbled the ball when his knee hit the ground, negating the "down by contact" rule.
"We made some plays on defense, Zoom (Jerry Azumah) caused a fumble, Vasher had a touchdown, we had a lot of pressure on the quarterback," Bears linebacker Brian Urlacher said. "It's easy when you get second and long and third and long to get to the quarterback a little bit."
Krenzel's very first pass was a perfectly thrown play-action 49-yard bomb to rookie wide receiver Bernard Berrian for a 7-0 Bears lead.
"It was a great route by Bernard, a great catch, the offensive line did a great job in protecting to give me time to let that ball go," Krenzel said. "But so early in the game like that you can't relax, you can't blow off some steam because it was the first touchdown pass or whatnot. We still had three and a half quarters, almost a full game ahead of us."
Krenzel quickly reverted to rookie form later in the first quarter by failing to protect the ball properly on a sack. He fumbled after being hit by 49ers linebacker Brandon Moore, fumbled again as he was hit by Bryant Young, and the 49ers' Dwaine Carpenter picked it up and returned it 80 yards for the game-tying points.
"I'm very disappointed in the way that I protected the ball," Krenzel said. "You know that, fumble in the pocket, I can't have that."
Then a badly overthrown Krenzel pass over the middle was picked off by free safety Ronnie Heard and returned 14 yards to set up a 49ers 10-7 lead. Todd Peterson kicked a 48-yard field goal with 40 seconds left in the first quarter.
The teams exchanged 51-yard field goals that banked off the crossbars, then Edinger kicked a 45-yard field goal with 4:35 left in the first half after Azumah had returned a kickoff 73 yards to the 49ers' 23.
Through three quarters the Bears' defense had held San Francisco to 89 net offensive yards, including 34 on the ground. The Bears had come into the game having allowed 100-yard rushing performances in four of their previous five games.
Thomas came into the game having rushed for no more than 17 yards in any game this year, and having carried no more than five times in a game.
However, his 16-yard run on the first play after McQuarters' 14-yard punt return set the Bears up with a first down at San Francisco's 23-yard line with 2:16 left in the third quarter.
That four-minute drive ended in Edinger's 27-yard field goal for the decisive points.
The 49ers had a chance to tie the game at 13-13 with 11:10 left but Peterson's 50-yard field goal fell short and wide right.
One play prior, Dorsey completed a first-down pass on third-and-seven, but replay overturned the catch, forcing a field goal try.
"We feel really good about this win and we're anxious to get on the field next week and play a real good Giants team,'' Smith said.