SAN DIEGO -- The Arizona Diamondbacks didn't get a hit in their final 24 at-bats. But it was a fielding gaffe that sunk them in extra innings against the San Diego Padres.
Alexi Amarista delivered with his first walk-off hit in the 11th inning, giving the Padres a 3-2 victory over the Diamondbacks on Thursday before 21,393 at Petco Park.
A.J. Pollock's misplay of a fly ball by pinch-hitter Jesus Guzman led to Amarista's winner and sent the Diamondbacks to their eighth setback in 10 games this season at Petco.
Pollock said he simply lost the ball.
"It just disappeared. It was like going into a room and then shutting the lights off," Pollock said. "I feel bad because I'm out there trying to make a play for (reliever Josh) Collmenter. It's pretty frustrating, but I don't know what else I could have done.
"It's tough. I hate losing. Hate giving up runs for my team. But I wish there was something I could have done."
Tommy Medica led off the 11th with an infield single against Collmenter. Guzman hit a deep fly near the warning track, but Pollock failed to make the catch as the ball dropped and bounced over the center field wall for a ground-rule double. That put runners at second and third.
After an intentional walk to Nick Hundley loaded the bases, Amarista singled up the middle of the drawn-in infield.
"I was ready for a change-up," said Amarista, who is 5-for-6 with the bases loaded this season. "Thank you, thank you, thank you."
Martin Prado homered for the Diamondbacks, accounting for both of their runs. Arizona (80-79) scored only seven times during the series with the Padres (75-85) and dropped three of the four games.
"We know we have a hard time beating these guys here," Diamondbacks manager Kirk Gibson said. "And when you don't have an offense, it makes it hard on you."
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, who combined with Huston Street and Nick Vincent (6-3) to keep Arizona hitless. Vincent struck out three in the final two innings.
"Robbie threw the ball well," Padres manager Bud Black said. "Best curveball he's had all year. Threw some really good curveballs. He's got really good rotation on the curve. We like his stuff.
"And the bullpen did a nice job. No doubt that Luke, Huston and Nick (pitched) four innings of solid relief. Obviously, in a tight game, that's what it takes to win."
Collmenter (5-5) gave up a run and three hits in an inning.
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.
The Padres had a chance in the eighth when reliever David Hernandez issued a leadoff walk to Gyorko and hit Headley with a pitch. But Hernandez fanned Medica, Mark Kotsay and Hundley to end the inning.
The Diamondbacks played their club-record 25th extra-inning game of the season. They are 17-8 overall.
Arizona set a major league record for extra innings played (78) this season in Tuesday's 2-1 victory in 12 innings over the Padres. That broke the 1969 Minnesota Twins' mark of 76 extra innings.
NOTES: Kotsay, who is retiring at the end of his 17th major league season, started in left in his final home game. He 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).