SAN FRANCISCO -- Matt Cain endured more than his fair share of ups and downs during his decorated San Francisco Giants career.

Fittingly, he got one more of each in his final start Saturday.

Austin Hedges lashed a two-strike, two-run double with two outs in the ninth inning, sending the San Diego Padres to a 3-2 victory over the Giants that ruined Cain's on-field retirement party.

The win ended a five-game losing streak for the Padres and kept their hopes alive of winning all six series from the Giants this season. San Francisco won the series opener 8-0 on Friday night.

"It was weird, because you want him to pitch well, too. But you want to win the ballgame," Padres starting pitcher Jhoulys Chacin said of Cain. "It worked out perfectly."

Perfectly for the Padres, who trailed 2-1 entering the ninth after Hunter Pence had driven in runs with a second-inning fielder's choice and a seventh-inning single.

Giants closer Sam Dyson (3-4) retired the first batter he faced, but usually reliable shortstop Brandon Crawford threw wildly to first base on Christian Villanueva's slow roller, allowing him to reach second.

Villanueva was credited with a hit.

After Cory Spangenberg singled pinch-runner Matt Szczur to third, Dyson struck out Hunter Renfroe before Hedges' liner to right-center field barely eluded right fielder Pence, easily scoring both baserunners for a 3-2 lead.

"It was definitely an emotional roller coaster," Cain said of his big day. "Right now, I'm spent. I think I've used up most of the emotions today."

Padres closer Brad Hand pitched a 1-2-3 ninth inning for his 21st save.

After having announced his retirement earlier in the week, Cain shut out the Padres on two hits in five innings in his first outing since Aug. 29. He walked one and struck out four.

One day before his 33rd birthday, Cain did not get a decision for the 109th time in his career. He left with a lead on 44 of those occasions.

"This wasn't the first time he's thrown some shutout innings and didn't come away with a win," Giants manager Bruce Bochy lamented. "He's had some tough luck. We'll look back on this game as another memory of Matt Cain."

The career-long Giant will finish his 13th season with a 60-60 record in 179 career home starts and 104-118 overall.

A three-time champion as a Giant, Cain was pulled with a 1-0 lead after his five innings.

He was greeted at the dugout step by Bochy, who hugged him to indicate Cain's day was over.

Giants fans responded with a standing ovation, one upon which the Padres joined. San Diego beat Cain more times (14) than any other team.

"He's beaten us a lot of times," Padres manager Andy Green said of Cain. "You respect an opponent, especially when he's done it with class."

Cain's chances of winning a 105th game ended when rookie right-handed reliever Reyes Moronta served up a two-out, two-strike solo home run to Wil Myers in the top of the sixth, tying the score at 1.

The home run was Myers' 30th of the season and sixth in eight games at AT&T Park this season. No one has ever hit more at the 18-year-old ballpark in a single season.

The Giants pushed a go-ahead run across after the Padres pulled Chacin after six strong innings. He allowed one run and five hits, walking two and striking out six.

"I just tried to keep us in the game," Chacin insisted. "After he (Cain) went out, I knew we'd score some runs."

Padres right-hander Craig Stammen walked the first batter he faced, Ryder Jones, to lead off the Giants' seventh.

After pinch-hitter Orlando Calixte sacrificed Jones to second, he coasted in on Pence's ground single into center field.

The second RBI of the day was Pence's 67th of the season, tying him with Buster Posey for second on the team behind Brandon Crawford's 76.

Buddy Baumann (2-1), who pitched a scoreless eighth inning, got the win.

Posey had two hits for the Giants, who lost to the Padres for the 12th time in 18 games this season.

Myers had two hits for the Padres, who have won nine of their last 12 games in San Francisco. The Padres out-hit the Giants 8-6.

NOTES: In the San Francisco era of club history, Giants RHP Matt Cain will retire second in starts (331), third in inning pitched (2,085 2/3), third in strikeouts (1,694) and tied for fifth in wins (104). ... The only players with 10 or more years of major-league experience to play exclusively for the Giants in their West Coast history were Cain, 3B Jim Davenport, RHP Scott Garrelts and 2B Robby Thompson. ... 1B Wil Myers became the first San Diego player to hit 30 home runs in a season since 3B Chase Headley in 2012. ... The last Padre to hit six or more home runs in a season at San Francisco was LF Greg Vaughn, who had six at Candlestick Park in 1998. ... Ted Barrett, who was behind the plate for Cain's perfect game on June 13, 2012, also called the balls and strikes Saturday.