SAN FRANCISCO -- It was another surreal scene in a surreal season.

The Giants were walked off at their own ballpark after Trent Grisham crushed a three-run home run off Sam Coonrod in the bottom of the seventh inning, sealing a stunning 6-5 defeat in the nightcap of Friday’s doubleheader at Oracle Park.

• Box score

“This sucked,” manager Gabe Kapler said. “It was a gut-punch loss.”

The Giants took a 5-3 lead into the seventh behind a three-run home run by Wilmer Flores, but the Padres were serving as the home team since the game was a makeup of the Sept. 12 game that was postponed in San Diego due to a coronavirus scare.

Coonrod gave up a leadoff single to Tommy Pham, issued a one-out walk to Greg Garcia and then misplaced a changeup to Grisham, who hammered it over the right-field wall for a game-ending home run.

“It's a 2020 walk-off -- on the road in the seventh inning,” Grisham said. “It was just different. It got about halfway up in the air before I realized, hey, that's for a walk-off, being on the road, wearing road unis. It was just different."

Coonrod entered Friday with an 8.16 ERA this season, but Kapler felt he was the best remaining option in San Francisco’s gassed bullpen. Kapler had Tony Watson close out a 5-4 victory in the first game, and he used Caleb Baragar, Jarlín García, Shaun Anderson and Sam Selman before turning to Coonrod, who possesses the arsenal to be a dominant Major League reliever but has struggled with command issues. Tyler Rogers was off after pitching in three consecutive games, though Wandy Peralta was also available in that spot.

Kapler said Peralta was his “length” option and Coonrod was his “leverage” option, but it was clear that Coonrod, who was pitching for the fifth time in the last seven days, wasn’t sharp enough to get the job done.

"His key is getting in the zone and staying in the zone," Kapler said. "It's not his stuff, it never has been and never will be. He's 97 to 100, 101, with a wipeout changeup. His key to being an elite Major League reliever is just throwing a ton of strikes. It's also the thing that's holding him back from being an elite reliever right now, and Sam is well aware that that's the key to his success.

“We used our options, put it like that. Our guys are a little beat up down there. We’ve asked a lot of them. We’ve pushed them really hard. They’ve done everything they can to answer the bell.”

It was a devastating loss for the Giants, who were two outs away from cutting their magic number to one with two games left to play. Instead, the Giants (29-29) fell back to .500, only one game ahead of the Brewers (28-30) and Phillies (28-30) for the eighth and final playoff spot in the National League. Milwaukee and Philadelphia both hold tiebreakers over San Francisco by virtue of their superior intradivisional records.

Still, the Giants have proved to be a resilient bunch and have rebounded from several heartbreaking losses over the course of this season. They can still clinch a playoff spot Saturday with a win and Phillies and Brewers losses. Kapler said he’s confident that his club will find a way to get back on track following their latest stunner.

“I have a lot of faith that these guys are going to bounce back,” Kapler said. “We've done that all year. It's the furthest question from my mind that this would be a crushing blow that these guys can't come back from and be excellent the next few days. I believe wholeheartedly that that's exactly what's going to happen.”

The Giants trailed, 3-2, in the sixth when the Padres summoned lefty Drew Pomeranz, who entered Friday with a 0.00 ERA over 18 innings. But Donovan Solano sparked a two-out rally with an infield single that rolled down the third-base line and slipped through the fingers of Manny Machado as he attempted a barehanded grab. Pinch-hitter Austin Slater then drew a walk to put two on for Flores, who subsequently crushed a 1-0 fastball over the left-field fence to put the Giants ahead, 5-3, eliciting jubilant roars from the “road” dugout.

“You can't have a bigger hit than that,” Kapler said. “It was huge, in a high-pressure situation. He has a history of getting big hits like that. He was as clutch as they come in New York and Arizona, so his ability to stay focused in a situation like that is second to none. Wilmer is known for moments like that, and for good reason.”

It was the second go-ahead shot of the day for Flores, who also homered off Chris Paddack to put the Giants in front in the fourth inning of a 5-4 victory in Game 1. After receiving the first multi-year contract awarded by Giants president of baseball operations Farhan Zaidi, Flores now leads the team with 11 home runs in 53 games this season. He hit nine over 89 games with the D-backs in 2019.

“It’s definitely a good feeling,” Flores said. “Today it felt like we were playing in Game 7 of the World Series. A lot of energy. Unfortunately, the last game didn’t go our way, but we’ve still got tomorrow.”