The Bolts fell behind by 14 points early, made a late surge but ultimately lost their eighth game of the season when Broncos kicker Brandon McManus drained a 53-yard field goal, giving Denver a 23-20 win.
Michael Badgley appeared to force overtime when he made a 46-yard field goal with 14 seconds left.
However, on the ensuing possession, Chargers cornerback Casey Hayward Jr. was called for defensive pass interference on a deep ball from Lock to Courtland Sutton, putting the Broncos in position for the game-winning kick.
Chargers defensive coaches, led by defensive coordinator Gus Bradley, berated the officials as they left the field at the end of the game.
Describe the game in two words: Groundhog Day. The Chargers had lost seven games by one score this season, failing to take care of the football. Make it eight, as Sunday's setback offered more of the same. The Chargers turned it over twice in the first half, leading to 10 points for the Broncos. Philip Rivers threw his eighth interception in three games -- the first time he's done that in his 16-year career -- and Troymaine Pope muffed a punt. Linebacker Drue Tranquill also was called for a personal foul for roughing the punter that continued a Denver drive.
QB Breakdown: Making his 220th consecutive start, Rivers was not at his best. He completed 20 of 29 passes for 265 yards, with two touchdown passes and his 15th interception of the season on a would-be screen pass to Austin Ekeler. According to ESPN Stats & Information, Rivers' interception in the opening quarter was his 12th this season against a standard four-man pass rush. Only Jameis Winston has more (14). Rivers also lost by seven or fewer points for the 65th time in his career (regular season and playoffs), the most of any quarterback in the Super Bowl era.
Derwin James makes his debut: Playing for the first time since suffering a fractured right foot during training camp that required surgery, James made the start at strong safety, finishing with four combined tackles, including a tackle for loss.