Rivers went 24-of-32 passing for 284 yards, leading the Chargers to their first 2-0 start since 2006.
San Diego also benefited from two Jackie Battle rushing touchdowns.
The Chargers' defense effectively eliminated the Titans' running game. Quarterback Jake Locker led Tennessee with 21 rushing yards.
The signal-caller connected on 15-of-30 passes for 174 yards and a touchdown for the Titans (1-1).