The Chargers led 29-9 at halftime and overcame a fourth-quarter Eagles comeback to improve to 6-3.
Rivers engineered a 12-play, 66-yard drive to set up a 29-yard Nate Kaeding field goal with 33 seconds left.
LaDainian Tomlinson rushed for 96 yards on 24 carries with two touchdowns. Legedu Naanee and Mike Tolbert caught scoring passes, while Antonio Gates added seven receptions for 78 yards for the Chargers, who face an AFC West showdown at Denver next Sunday.
Philadelphia's Donovan McNabb went 35-for-55 for 450 yards and his two fourth-quarter touchdown passes drew his team within 28-23 with 7:18 left.
Brent Celek and Jeremy Maclin caught touchdown passes, and Jason Avant had eight receptions for 156 yards for the Eagles (5-4), who gained just 29 net rushing yards.