Arizona forced extra innings with a three-run rally in the ninth, in which two runs were scored on an error by Headley, but fell to bases on balls. Diamondback pitchers walked 10 in the game and walks figured in all three of the Padres' run-scoring innings.
Chris Denorfia started the final rally with a one-out single in the 11th and Will Venable followed with another base hit off Sam Demel (1-2). After another out, in which the runners advanced, Ryan Ludwick reached on catcher interference, loading the bases for Headley.
Headley worked the count full and Demel's final pitch was well outside, forcing in the winning run and handing the victory to Chad Qualls (1-2), who pitched two innings of one-hit relief.
The Arizona ninth was nearly as improbable. Gerardo Parra had doubled in the Diamondbacks' first run. Then, with the bases loaded and two outs, Kelly Johnson hit an easy grounder to Headley at third but his throw to first was low and Brad Hawpe was unable to handle it. Two runs scored and tied the score at 3-3.
San Diego's first run in the third also came on an error when a sacrifice bunt was misplayed. Venable followed with a sacrifice fly. Headley had an RBI single in the fifth that made the score 3-0.
Notable deaths of 2014 [PHOTOS]