SANTA CLARA, Calif. - After the Chargers scored on Antonio Gates' second touchdown of the night with 5:21 left in the fourth quarter cutting the lead to 7, the 49ers got a 57-yard kickoff return from Perrish Cox to the Chargers' 45-yard line.
All the 49ers needed was a first down, which would have put them in field goal range to make it a two-score game, and to keep the clock moving. They would have likely been able to salt the game away with simple execution.
It's been a reoccurring theme for San Francisco this season - little mistakes compounding into immense consequences.
On third-and-5 from the Chargers' 40, the 49ers dialed up a designed run for Colin Kaepernick, who sprinted left, where the Chargers had two defenders there to prevent him from making a big play.
It was a similar situation to 11 months ago, when Kaepernick was in frigid Green Bay in the Wild Card round of the playoffs and made a crucial third-down conversion with his legs that set up Phil Dawson's game-winning field goal as time expired.
Only this time, Kaepernick was unable to get the first down, which wasn't his biggest mistake on the play. He ran out of bounds, stopping the clock with 3:43 left. Had he stayed in bounds, Philip Rivers would have had 40 fewer seconds to work with. Or one less timeout. San Diego used all three of their timeouts on that final scoring drive, including just before the game-tying play.
Rivers capped his four-touchdown, 356-yard night with :29 remaining in regulation when he hit Malcolm Floyd for the game-tying touchdown before San Diego won the game in overtime. The Chargers drove 80 yards on 14 plays, taking 3:01 off the clock.
San Francisco lost the game, 38-35, after another crucial mistake in overtime, when Quinton Patton fumbled at San Diego's 38-yard line giving the ball back to Rivers, who had 273 second-half yards in the air. The Chargers went 40 yards and ended the game on Nick Novak's 40-yard field goal.
"They chose to give me the ball and I wanted to make a play," Patton said. The 49ers' first-team offense has still not scored a passing touchdown in the fourth quarter. Saturday, they scored just seven points after halftime.
Kaepernick's other notable mistake was his eighth fumble of the season, when defensive lineman Corey Liuget recovered the ball in the end zone for a touchdown that made it a 28-21 game late in the third quarter. Kaepernick was sacked by Ricardo Mathews and Dwight Freeney after trying to extend the play and holding on to the ball.
The strip-sack came one play after a 63-yard touchdown to Vernon Davis was negated by two penalties - a Frank Gore chop block and illegal formation on right tackle Anthony Davis, who made his first start since Nov. 16. It was a crucial 14-point swing that dramatically altered the game.
Three plays later, it appeared Kaepernick made up for the sack and fumble when he escaped for a 90-yard touchdown, the second-longest in team history, after Garrison Hearst's 96-yard overtime run in 1998's season opener. It was Kaepernick's first rushing touchdown of the season, and also his first biceps kiss after he initially thought the play was coming back with a flag, but it turned out to be a defensive hold on San Diego.
"I thought (the game) was over," Gore said about Kaepernick's run. "I am happy for Kap, he looked like himself out there. I thought it was over."
The Chargers capped a 21-point comeback after the 49ers dominated in the first half, heading to the locker room up 28-7. But it could have been even worse for San Diego, had Bruce Miller not fumbled near the goal line on the 49ers' second drive of the night.
One first-and-goal from the 5, Miller ran a misdirection run up the middle and had a lane to the end zone. But Chargers' safety Marcus Gilchrist put his helmet on the football and forced a fumble Liuget recovered at the 5.
San Francisco came away with no points, not even a field goal, before falling in overtime by three.
"If you turn the football over you probably won't win games, and I was the culprit down on the 5-yard line," Miller said. "You have to take care of the football.
"...We gave them some air, let them breathe."