Drew Brees led a 2-minute drive capped off by his one-yard leap into the endzone with :14 seconds remaining in the first half. The Saints other points came courtesy of a 48-yard Wil Lutz field goal on the final play of the first quarter.
Chargers rookie QB Justin Herbert is 9 of 13 for 109 yards and three touchdowns.
The Chargers third touchdown was set up when Nasir Adderley picked off Brees and returned it 34 yards to the 1-yard line.
New Orleans will get the ball to start the second half.
The Saints lost guard Nick Easton to a concussion in the second quarter.