Padres 8, Diamondbacks 2: Rookie Andrew Werner allowed three hits in 6 1/3 innings and Chase Headley hit a grand slam as host San Diego won the rubber game of the three-game series.

Werner (2-1) gave up one run and struck out six in his fourth major-league start. The Padres blew it open with a five-run seventh that was highlighted by Headley’s third career grand slam and 27th homer this season. San Diego has won five of its past six series and improved to 14-5 since Aug. 19.

Patrick Corbin (5-7) dropped to 0-3 in his last five starts, surrendering three runs on six hits in 5 1/3 innings. Arizona has dropped 11 of 16.

Cameron Maybin doubled down the left-field line in the second, scoring Carlos Quentin to put the Padres ahead 1-0. Andy Parrino brought home Jesus Guzman with a sacrifice fly later in the inning to double the advantage.

Arizona pulled within 2-1 on Jason Kubel’s RBI groundout in the third. The Padres pushed the lead back to two runs in the sixth on Chris Denorfia’s seventh homer. Quentin followed Headley's grand slam in the seventh with his 16th blast.

Maybin and Quentin had two hits apiece for the Padres. Adam Eaton, Chris Johnson and Miguel Montero each finished with two hits for Arizona.

GAME NOTEBOOK: Headley’s grand slam pushed his season RBI total to 102. … San Diego leads the season series 10-5. The National League West rivals meet Sept. 18-20 at Arizona. … The Padres are three games behind the Diamondbacks for third place in the NL West. … The Diamondbacks return home Tuesday to face the Dodgers. … San Diego continues its nine-game homestand with a three-game series against St. Louis, starting Monday.