SAN FRANCISCO -- The sting of seeing the opposition celebrate back-to-back walk-off wins in two different cities -- in games the Astros seemingly had in control -- underscores how things continue to go wrong this season, even when they do so many things right.

The Astros got 5 2/3 innings of one-run ball from rookie starter Spencer Arrighetti on Monday night and pushed across two runs in the top of the 10th inning by using a pair of bunts and a sacrifice fly, giving themselves an 84 percent win probability. Closing out a two-run lead proved to be problematic for the second game in a row.

With closer Josh Hader having already thrown the ninth inning and setup men Bryan Abreu and Ryan Pressly having pitched in two consecutive games, Rafael Montero started the 10th with a two-run lead. He was tagged for three runs and four hits -- he also made a fielding error -- to give the Giants a 4-3 win over the Astros at Oracle Park.

“Just a tough loss,” Astros manager Joe Espada said. “Just couldn’t make pitches there and couldn’t get out of that inning. Just a really tough loss.”

Austin Slater won it for the Giants when he clubbed a sinker from Montero off the left-field wall with the bases loaded for what was scored a walk-off single. The Angels walked off the Astros on Sunday in Anaheim when Logan O’Hoppe hit a two-run homer off Hader, with the ball getting knocked from the glove of left fielder Trey Cabbage and going over the wall.

The Astros fell to 5-14 in one-run games and 3-6 in extra-inning games -- the most extra-inning losses in the American League. Houston suffered consecutive walk-off losses for the first time since Sept. 25-26, 2021, at Oakland.

“It’s tough,” Cabbage said. “We fought all game and they got us in the end.”

What made Monday’s loss even more frustrating is how well the Astros executed some small ball in the top of the inning. Houston had yet to bunt in extra innings this year before Cabbage -- leading off the 10th with automatic runner Joey Loperfido at second base -- beat out a bunt single to put runners on the corners.

“I knew we had the top of the lineup behind us and I just wanted to get them 90 feet closer to be able to knock them in, and luckily enough I beat it out,” Cabbage said.

Victor Caratini’s sacrifice fly put the Astros ahead, and Alex Bregman added an RBI single to score Cabbage -- after Jose Altuve bunted for a hit to move Cabbage to third. It was the first time the Astros bunted twice in the same extra inning since Sept. 26, 2011, when Jason Bourgeois and Angel Sanchez had consecutive bunts to walk it off in the 10th to beat the Cardinals.

“We talked about it in the dugout,” Espada said. “With a lefty [Erik Miller] on the mound, we were just trying to get the guy over and get yourself a chance there by bunting them over. A well-executed bunt.”

The Astros led, 3-1, going to the bottom of the inning and handed the ball to Montero, who allowed five of the six batters he faced to reach base.

“I just like Montero against that pocket there, against those lefties especially,” Espada said. “We relied on him before and he’s the right guy for that spot there. Just wasn’t his night.”

Arrighetti kept the Giants off the scoreboard for 98 pitches. His 99th and final pitch of the game was a curveball hit into the right-center-field gap by Mike Yastrzemski for a triple to score Jorge Soler. Arrighetti gave up four hits and three walks and struck out six in 5 2/3 innings.

"I own that one,” Arrighetti said of his final pitch. “I went against the game plan there and it bit me. I feel like I had handled him right up to that point and I knew that's what he was looking for, and I still felt like the risk-reward was there. I took a chance. Bit me. Yeah, won't happen again."

Meanwhile, Giants starter Kyle Harrison held the Astros, who are without slugger Kyle Tucker (shin contusion), scoreless for six innings. Yordan Alvarez led off the seventh with a triple to right-center and scored on a sacrifice fly to center by Jeremy Peña.

“We put some really good at-bats together, putting some extra runs on the board,” Esapda said. “It just wasn’t enough.”