SAN FRANCISCO – The Giants remain on the fringes of the playoff picture, but they’re intent on showing that they have plenty of fight left. 

Thairo Estrada launched a two-run, walk-off home run off of Wil Crowe in the bottom of the ninth inning to propel the Giants to a wild 8-7 comeback victory that completed a three-game sweep of the Pirates on Sunday afternoon at Oracle Park.

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The Giants blew a five-run lead behind another hiccup from their bullpen and then watched the Pirates score the go-ahead run in the ninth on a throwing error from third baseman Evan Longoria, who airmailed a throw to first base while attempting to field an infield single from Rodolfo Castro.

But Estrada saved the day in the bottom of the ninth, crushing a first-pitch sinker from Crowe to left field to end the back-and-forth affair and lift the Giants (57-57) back to .500 for the first time since Aug. 1. It was the first career walk-off homer for Estrada, who was mobbed by his euphoric teammates after crossing home plate.

“It’s nice to see Estrada come up in a big spot and hit a home run like that,” manager Gabe Kapler said. “I think he’s been so dependable for us. It’s rare that he gets to be the star of the game. … In that situation, you don’t expect a home run, but you probably should now. He does hit homers, he does hit homers in big spots. It shouldn’t surprise us anymore because he’s come up in big spots and put the ball in the seats.

“I do think it’s a signal that there’s a lot of fight still left in that room.”

The Giants, who have won six of their last eight games, remain six games behind the Phillies for the third National League Wild Card spot, but they feel they still have the pieces to make a late push in the playoff race, particularly now that their roster is close to full health. They’ll have an opportunity to continue to make up ground in the coming weeks, as their next nine games will come against a trio of sub-.500 clubs in the D-backs, Rockies and Tigers.

“It’s been an up-and-down year, obviously,” left-hander Alex Wood said. “I think days like today, when you get a walk-off homer like that, you’ve got to be in the moment and let that ignite you a little bit. It was really nice to get a good sweep here at home and hopefully get something going here. I think it’ll be a big next two weeks for us.”

The Giants jumped out to a 5-0 lead behind LaMonte Wade Jr.’s three-run homer and RBI doubles from Tommy La Stella and Wilmer Flores, but the Pirates pulled within two after scoring three runs off Wood in the fifth.

Still, the Giants’ gassed bullpen couldn’t hold the lead after Wood exited following six solid innings. John Brebbia, who leads MLB with 55 appearances this year, faced four batters without recording an out in the seventh, surrendering a three-run shot to former San Francisco prospect Bryan Reynolds that put the Pirates ahead 6-5. Reynolds’ blast traveled a projected 442 feet out to right-center field, making it the longest homer hit at Oracle Park this season.

The Giants were gifted the tying run in the home half when Brandon Crawford hit a two-out popup that dropped behind shortstop Oneil Cruz and second baseman Kevin Newman in shallow center field, resulting in an RBI double that made it 6-6.

Their own defensive shortcomings nearly cost them in the top of the ninth, though Longoria redeemed himself by kicking off the decisive rally with a leadoff single in the bottom of the ninth. Two batters later, Estrada capped the comeback with his 11th home run of the year.

“It was my first walk-off, so obviously I enjoyed every minute of it,” Estrada said. “As soon as I made contact, I knew it was gone.”

The Giants still have a long road ahead, but this weekend’s results helped boost their confidence in their ability to remain resilient and put together a serious playoff run down the stretch.

“We go out and give 100 percent every day,” Estrada said. “We know what kind of team we have and what we’re capable of. The most important thing is to stay positive and keep fighting from the first to the ninth inning.”