SAN DIEGO -- Alexi Amarista hit a walk-off single in the 11th inning, giving the San Diego Padres a 3-2 victory over the Arizona Diamondbacks on Thursday before 21,393 at Petco Park.
Tommy Medica led off the the 11th with an infield single against reliever Josh Collmenter. Pinch-hitter Jesus Guzman hit a fly ball to the wall in center that A.J. Pollock misplayed into a ground-rule double, putting runners at second and third. After an intentional walk to Nick Hundley, Amarista singled up the middle for the winner.
Martin Prado homered for the Diamondbacks, accouting for both of their runs. The Diamondbacks (80-79) scored only seven runs during the series with the Padres (74-85) and dropped three of the four games.
Prado's home run was one of the few mistakes by Padres starter Robbie Erlin. The left-hander struck out seven and limited Arizona to three hits and one walk in seven innings. After Prado went deep, Erlin retired the final 12 batters he faced before being relieved by Luke Gregerson.
Nick Vincent (6-3) worked two hitless innings as the Padres' bullpen shut down the Diamondbacks, who didn't get a hit in their final 24 at-bats.
Collmenter (5-5) gave up a run and three hits in an inning.
The Diamondbacks (80-79), who lost six of their past seven at Petco and eight of 10 overall, didn't have a hit in their last 24 at-bats.
Arizona starter Trevor Cahill, who grew up in the San Diego area, allowed two runs and five hits with four walks and three strikeouts in 5 2/3 innings.
The Padres opened a 1-0 lead in the third when Jedd Gyorko's seeing-eye single with two outs scored Chris Denorfia, who had tripled. Chase Headley followed with an RBI double to right, scoring Gyorko, for a 2-0 advantage.
After Arizona's Paul Goldschmidt extended his hitting streak to 16 games with a single to right to lead off the fourth, Prado homered to left to tie the score. It was Prado's 14th home run of the season, leaving him one short of tying his career high of 15 in 2010.
NOTES: Padres OF Mark Kotsay, who is retiring at the end of the season, started in left in his final home game. Kotsay, who is completing his 17th major league season, was honored during a pregame ceremony. ... Padres RHP Burch Smith (1-2, 5.87 ERA) will face Giants RHP Ryan Vogelsong (3-6, 5.90) in the opener of a three-game series on Friday in San Francisco. ... The Diamondbacks head home for their final series starting Friday when they host the Nationals. Washington RHP Stephen Strasburg (7-9, 3.02) will face Diamondbacks LHP Patrick Corbin (14-7, 3.28).