The Chargers (7-3) overtook Denver (6-4) for first place in the AFC West.
Rivers completed 17-of-22 passes for 145 yards, throwing a 2-yard scoring pass to Legedu Naanee with 5:58 left in the first period. LaDainian Tomlinson rushed for 73 yards on 20 carries, scoring on a 1-yard run in the third.
Mike Tolbert scored a touchdown and Vincent Jackson caught four passes for 56 yards, while the Chargers' defense forced three turnovers.
Kyle Orton, playing on a gimpy right ankle, completed 15-of-29 passes for 171 yards, no touchdowns and one interception.
Knowshon Moreno gained 80 rushing yards and Matt Prater kicked a third-quarter field goal, while Chris Simms lost a fumble in the end zone for the Broncos, who have lost four in a row.