SAN FRANCISCO The 49ers' offense wasn't exactly rolling when Vernon Davis was in the game Sunday. When the tight end left with a concussion at the end of the second quarter, it fell apart.
Facing a powerful Carolina defense and without one of his few trusted targets, Colin Kaepernick and the 49ers converted just two third downs and finished with 46 net passing yards in the 10-9 loss.
"Unacceptable," receiver Anquan Boldin said.
"We didn't execute," Kaepernick said.
"It's just a sinking feeling," Jim Harbaugh said.
The loss dropped the 49ers 2 1/2 games behind the Seahawks big winners against the Atlanta Falcons on Sunday in the NFC West and brought to a halt their five-game winning streak. San Francisco scored 30 or more points in each of those victories.
Against Carolina, the 49ers could manage only three field goals.
Their best shot at a touchdown came in the second quarter after cornerback Tramaine Brock picked off Carolina's Cam Newton and returned the ball to the Panthers' 24-yard line. But facing fourth and 1 at Carolina's 2-yard line, the 49ers only bluffed going for the conversion and settled instead for a short Phil Dawson field goal.
At the time, the 49ers didn't have Davis, who had gone to the sideline after being dragged down hard two plays earlier. They also were without blocking tight end Garrett Celek, who suffered a hamstring injury in the first quarter, and Harbaugh later said the 49ers simply didn't have the right personnel for a short-yardage conversion.
It was clear that Davis' absence also affected Kaepernick and the passing attack.
Trailing by a point, the 49ers had three opportunities in the fourth quarter for a go-ahead drive. Kaepernick, however, had only two completions on those three drives and was sacked twice. The final desperation drive with 1:02 remaining consisted of a Kaepernick sack and an interception on a pass to Mario Manningham.
It was a microcosm of the larger game. Kaepernick was sacked six times overall, the most of his career. He was sacked four times last year in a win over Miami.
With Davis out and the Panthers rolling their coverage to Boldin, Kaepernick was forced to look for other targets, something he has struggled to do this season. One was Manningham, who was playing his first game since suffering two torn knee ligaments in a Dec. 23 loss to Seattle.
Manningham finished with three catches for 30 yards, but he also had two drops.
Davis entered Sunday's game trailing only Boldin among 49ers pass catchers in receptions and receiving yards. His seven receiving touchdowns lead the 49ers. He suffered a hamstring strain in the Week 2 loss to Seattle and sat out the following week's loss to Indianapolis. The 49ers scored 10 points total in those games.
"Vernon changes defenses," Kaepernick said. "He makes them adjust differently. He makes them do things that they don't normally do. He's a big loss."
Perhaps the 49ers were lucky to lose by just one point.
The Panthers dropped an easy interception on the 49ers' opening drive. San Francisco also benefited from a deflected punt that glanced off a Carolina player and gave the 49ers a fresh set of downs. And they got a break when officials ruled that what seemed to be a Davis fumble actually was an incomplete pass.
Now they will set off on back-to-back road games, the first a trip to New Orleans to face a Saints squad that also is jockeying for playoff position in the NFC.
"It's a loss. It's no fun," linebacker Patrick Willis said. "But it's part of the game. It's adversity, and we have the team to fight and get through it."
Read Matthew Barrows' blogs at www.sacbee.com/sf49ers and listen for his reports Tuesdays on ESPN Radio 1320.