SANTA CLARA, California — Colin Kaepernick has delivered two drastically different performances in prime time against the Chicago Bears, from that sensational first career start two years ago at Candlestick Park to the complete debacle in his Levi's Stadium debut.
He found only one word to describe it Sunday night: "Terrible."
Kaepernick threw two of his three interceptions in the fourth quarter and also lost a fumble, watching Jay Cutler rally the Bears from a late double-digit deficit to a stunning 28-20 win to spoil the first regular-season game in the 49ers' new $1.2 billion stadium.
Cutler connected with Brandon Marshall for two of his three fourth-quarter touchdown passes after much of Chicago's starting defense went down.
Cutler and Marshall clicked as Chicago erased a late 13-point deficit and quieted the sellout crowd. Cutler threw for two scores in a 27-second span early in the final period, aided by the gutsy play of a backup cornerback.
Kyle Fuller made two late interceptions for the depleted Chicago secondary, and the first set up the go-ahead score.
"It stings to lose and we all had fingerprints on it," 49ers coach Jim Harbaugh said. "I think we're all going to look at this one and feel we have fingerprints on it. I can't really single out anything."
Kaepernick was hit with an unsportsmanlike conduct penalty for "inappropriate language" following Fuller's first big play. That gave the Bears first-and-goal on the 3, and Cutler threw a 3-yard TD pass to Martellus Bennett as the Bears went ahead 21-20.
Kaepernick's performance was a far cry from his breakout start on the Monday night stage nearly two years ago in a rout of the Bears. Cutler sat out that night with a concussion.
"We hurt ourselves," Kaepernick said, insisting he didn't say anything wrong.
A sloppy game filled with 26 penalties — 16 for 118 yards by the Niners — and a crazy collapse overshadowed the fanfare.
"This is very disappointing, our first game in the new stadium," linebacker Patrick Willis said. "We put the loss on us as a football team. ... We have to cut down on the penalties."
The Bears (1-1), in a stretch with six of eight games on the road, go home with some serious momentum despite injuries on both sides of the ball. Cutler finished 23 of 34 for 176 yards.
Five key defenders are hurt: cornerbacks Sherrick McManis (quadriceps) and Charles Tillman (triceps), defensive end Trevor Scott (foot), safety Chris Conte (shoulder) and defensive tackle Jeremiah Ratliff (concussion). Trestman had no updates.
The 49ers (1-1) had a 17-7 halftime lead, but missed an opportunity to grab an early lead in the NFC West after the defending Super Bowl champion Seattle Seahawks lost earlier in the day at San Diego.
"That's not our style of football," right guard Alex Boone said.
Michael Crabtree caught a touchdown pass on his 27th birthday for one of his seven receptions and Frank Gore ran for a score but also had his 54-yard TD burst negated by Anquan Boldin's costly holding penalty.
"We felt like we gave the game away," Boldin said.
Cutler helped the Bears get on the board with a 25-yard run late in the first half. He took a jarring hit from Quinton Dial with 56 seconds remaining, but stayed in the game and threw a 17-yard touchdown pass to Marshall, who made a leaping, one-handed catch to pull the ball into his body as he fell into the end zone.
"I just threw my hand out there and it stuck," Marshall cracked.
San Francisco didn't give the ball away once in a season-opening win at Dallas.
In the first half, the 49ers outgained Chicago 197-93 and out-penalized the Bears 10-7 for 85 lost yards. The much-scrutinized field featured visible chunks of loose sod after new grass was laid for a third time since April.
Kaepernick made his first career start against the Bears in November 2012, and then held onto the No. 1 job over Alex Smith.
A concussion to now-Chiefs QB Smith thrust Kaepernick into the spotlight that night, and he threw for 243 yards and two touchdowns as the Niners pounded the Bears 32-7.
The 49ers were embarrassed at home for the second time in a month. They lost 34-0 in a rout by Denver in the first preseason game in the new stadium.
"We've got to clean it up and move on," Gore said.
Notes: San Francisco tight ends Vance McDonald (knee) and Vernon Davis (left ankle) were hurt. Davis was on crutches afterward in the locker room. ... The 49ers lost a home opener for the first time under fourth-year coach Harbaugh.