The Chargers trailed 31-20 before Darryl Gamble recovered a Richard Bartel fumble in the Cardinals’ end zone midway through the fourth quarter.
With 3:11 remaining, Volek led San Diego on a 12-play, 90-yard drive to account for the winning score. In all, Volek completed 9-of-17 passes for 123 yards.
Philip Rivers also performed well for the Chargers, throwing for 198 yards and a pair of second quarter scores to Antonio Gates and Malcom Floyd.
Rivers’ counterpart, Arizona quarterback Kevin Kolb, was equally effective. Following early field goals from Jay Feely and Nate Kaeding, the former Philadelphia Eagle gave the Cardinals a 10-3 lead when he connected with Larry Fitzgerald for an 80-yard touchdown pass.
Fitzgerald finished with three catches for 108 yards.
Patrick Peterson intercepted a Rivers’ pass and returned it 34 yards for a score to give the Cardinals a 17-3 advantage after one quarter.
Andre Roberts reeled off a 34-yard touchdown run in the second quarter and LaRod Stephens-Howling caught a fourth quarter scoring strike from Bartel to account for Arizona’s final tally.
Kaeding booted a 36-yard field goal in the third quarter.