For 7 minutes, 7 seconds, the 49ers' offense looked well-oiled and ready for the Green Bay Packers in Week 1 of the regular season. Then, Colin Kaepernick threw on his cap.
One of the NFL's most celebrated quarterbacks took 13 snaps against the Denver Broncos at Candlestick Park on Thursday, leading the offense on a 62-yard drive that ended in a field goal before handing the keys over to backup Colt McCoy. After that, the offense sputtered, turning the ball over four times en route to a 10-6 loss in the preseason opener.
"Execution was good," coach Jim Harbaugh said, referring to the opening series. "I'm happy with the first-team offense."
Kaepernick played one series, completing each of his four passes for a total of 38 yards. He hooked up with wide receiver Anquan Boldin twice for 14 yards and he connected with tight end Vernon Davis for a 12-yard gain.
The 25-year-old quarterback's most impressive pass came on third-and-16 from inside the Broncos' 30-yard line. Kaepernick threw a 12-yard strike across his body while scrambling to his right to evade Broncos linebacker Von Miller., hitting Marlon Moore, who started at wide receiver alongside Boldin.
Kaepernick also picked up a first down on third-and-2 with a 6-yard scramble.
"It was just good to be back out on the field," Kaepernick said.
Running back LaMichael James, who started in the backfield in place of Frank Gore, also appeared to be in midseason form. James picked 24 yard on five carries in the first series. He finished the game with 27 yards.
The 49ers' starting defense, which was missing Patrick Willis (hand) and Justin Smith (finger), held Peyton Manning's offense to 22 yards in the veteran's quarterback's lone series under center.
The defense forced a punt after Aldon Smith, who played the last two months of the 2012 season with a torn labrum, broke through the Broncos' line, disrupting Manning's throw with a hit on third-and-9.
"The defense played outstanding," Harbaugh said.
Colt McCoy took over for Kaepernick late in the first quarter. He threw an interception before leaving the game at halftime with a shoulder injury. He will undergo an MRI on Friday to determine the severity of the injury.
The Broncos scored the only touchdown of the game midway through the second quarter when linebacker Shaun Philips recovered an Anthony Dixon fumble at the 49ers' 9-yard line and ran it in for six.
The 49ers turned it over two more times: A.J. Jenkins fumbled in the second quarter and Scott Tolzien threw an interception in the third.
Veteran kicker Phil Dawson hit 2-of-3 field-goal attempts in his 49ers debut.