SAN FRANCISCO -- It’s been a challenging year for the Brandons, but the veteran duo came through for the Giants in a 4-3 walk-off win over the D-backs on Wednesday at Oracle Park.

The Giants trailed 3-0 for most of the afternoon, before Brandon Belt kicked off the comeback with a solo shot off right-hander Zac Gallen in the seventh. After David Villar’s sacrifice fly gave the Giants another run in the seventh before Gallen exited, and Wilmer Flores’ pinch-hit homer tied the game in the eighth, Belt led off the ninth with a single against Arizona closer Mark Melancon, setting the stage for Brandon Crawford’s heroics.

A double by Mike Yastrzemski and a walk by Villar loaded the bases with one out for Crawford, who lined a single to right field to score Belt and give the Giants their first series victory since June 17-19 at Pittsburgh.

“Everybody knows this is who we are,” Flores said. “We’re always trying to find ways to win with good pitching and timely hitting. Things haven’t been going our way, but we know this is who we are.”

The gritty win was reminiscent of 2021, when the Giants rode resurgent veterans, a deep bench, strong pitching and clean defense to a franchise-record 107 wins. San Francisco has tried to stick to a similar playbook this year, though the results haven’t been the same -- the club entered Wednesday having lost 15 of its past 22 games, falling 1 1/2 games behind the Cardinals for the final National League Wild Card spot.

But with four wins in their last five games, the Giants believe they’re starting to come out of their downturn and building some much-needed momentum as they prepare to close out the first half with a four-game series against the first-place Brewers that begins on Thursday.

“I think we’re seeing some signs of that,” Belt said. “We’ve been seeing it for the last few days. I think when you have a game like this, though, it’s really something that can pick up the confidence a lot. I know there are a lot of people that don’t believe in momentum anymore, but that’s what we’re hoping we have right here.”

With Anthony DeSclafani out with a season-ending ankle injury, the Giants turned to their bullpen to cover the open spot in the rotation on Wednesday. John Brebbia opened the game with a scoreless first before giving way to Sam Long, who gave up three runs over 1 2/3 innings. The relief corps put up zeros the rest of the way, though, with Tyler Rogers, Jarlín García, Mauricio Llovera and Camilo Doval combining to toss the final 6 1/3 innings.

Gallen allowed only one hit -- a second-inning double from Thairo Estrada -- through his first six innings, before Belt finally put the Giants on the board with his seventh home run of the year. Belt has made his last two starts at designated hitter as he tries to manage swelling in his troublesome right knee, but he’s continuing to heat up at the plate, where he’s now 8-for-11 with two doubles and two home runs over his last four games. The 34-year-old had gone only 7-for-47 (.149) in his first 19 games since returning from the injured list, but he had remained confident that he was close to breaking out of the rut.

“It obviously sucks going through a slump, but I’ve been through a lot of them, and I’ve always come out of them,” Belt said. “It was more just kind of reassurance for myself a little bit. I knew it was a matter of time.”

The Giants emptied the bench in the eighth, with Flores, Darin Ruf, Yermín Mercedes and Luis González each making pinch-hit appearances to try to capitalize on as many platoon advantages as possible. Flores delivered a game-tying blast off lefty Joe Mantiply, though the Giants were left with no pinch-runner options once Belt singled to open the ninth.

Manager Gabe Kapler admitted that he considered using reliever Yunior Marte, who was unavailable to pitch after working two innings on Tuesday night. But he ultimately stuck with Belt, who subsequently advanced from first to third on Yastrzemski’s double off the right-field wall.

“I’m just slow,” Belt said. “It’s just the way it is right now.”

Crawford has also been enduring a tough stretch, and entered Wednesday with a .644 OPS this year, but he still showed his penchant for big hits, coming through with a walk-off single that allowed Belt to trot home and seal the Giants’ big win.

“It was one of those times that we battled,” Belt said. “We didn’t give up the entire game. We came back in the last inning. To see everybody clicking a little bit, that’s the kind of baseball we have to play to win ballgames.”