It wasn’t the Giants’ crispest victory of the year, but in the end, they were bailed out by outfielder Austin Slater, who picked an opportune time to break out of his prolonged slump.

The Giants blew an early four-run lead and committed a season-high three errors, but Slater crushed a go-ahead two-run home run with two outs in the eighth inning to lift San Francisco to a 6-5 comeback win over Arizona on Saturday night at Chase Field.

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Slater was mired in a 4-for-41 slump when he stepped up to the plate against left-hander Ryan Buchter, but he promptly blasted a 2-2 curveball to straightaway center field for a towering shot that traveled a Statcast-projected 463 feet and turned a one-run deficit into a 6-5 lead. It was the longest homer of Slater's big league career, eclipsing a 461-foot shot he delivered as a rookie at Milwaukee on June 8, 2017.

“I was just trying to battle and get something hanging that I could put a good swing on,” Slater said during a postgame interview on NBC Sports Bay Area. “I’ve been grinding, working my [butt] off in the cage. I just haven’t seen the results on the field. But it was great to see that pay off a little bit tonight and hopefully, keep it going.”

Slater’s heroics allowed the Giants to retain their hold of first place in the National League West, remaining a half-game ahead of the surging Dodgers, who have won eight games in a row.

Thairo Estrada nearly undermined the late rally after he was picked off at first base for the second out of the eighth, but Mike Yastrzemski kept the line moving by drawing a walk off Buchter. That brought up Slater, who came through with his eighth home run of the year and his first since May 30.

Slater has established himself as one of the Giants’ most dangerous weapons against left-handed pitchers over the past two years, but the 28-year-old slumped badly in June, causing his batting average to tumble to .199 through his first 66 games of the season.

“In June, we didn’t see a whole lot of lefties,” Slater said. “I felt like I was starting to get my swing back at the beginning of June, and then we went on like a two-and-a-half, three-week stretch of not seeing any lefty starters. So for me, it’s just grinding in the cage and trying to keep the timing, trying to find a swing. If you don’t have your timing, making slight adjustments here and there. It’s been a work in progress, that’s for sure.”

A two-run home run by Yastrzemski ignited a four-run rally for the Giants in the third, but the D-backs countered with a pair of runs in the bottom of the inning. Then, Nick Ahmed’s two-run homer off Giants rookie left-hander Sammy Long tied the game at 4 in the fourth.

Arizona went ahead an inning later with the help of a rare defensive mistake from San Francisco first baseman LaMonte Wade Jr. Shortly after Asdrúbal Cabrera reached on a leadoff single, Pavin Smith hit a grounder down the right-field line that skipped between the legs of Wade at first base, putting runners on second and third with one out.

It was only the second error of the season for Wade, who is primarily an outfielder but has filled in capably for the injured Brandon Belt at first in recent weeks.

Manager Gabe Kapler summoned left-hander José Álvarez to try to limit the damage, but David Peralta subsequently delivered a bloop single to right-center field that sailed over the Giants’ drawn-in infield, plating Cabrera from third and giving the D-backs a 5-4 lead.

“I don’t think we played our crisp brand of baseball today on defense, on the bases,” Kapler said. “I just don’t think we were at our best, and we’re going to need to be better than that.”

The Giants went only 2-for-14 with runners in scoring position, but they got the knockout blow when they needed it most.

Slater didn’t start against D-backs right-hander Jake Faria, but he pinch-hit for Alex Dickerson when left-hander Joe Mantiply came on in relief to start the fifth. Kapler had two other right-handed bats -- Darin Ruf and Jaylin Davis -- on his bench at the time, but he decided to stick with Slater, who posted a 1.127 OPS against southpaws in 2020.

“We depend on Slater to get those kind of big hits against left-handed pitching,” Kapler said. “We really do believe in Slater, so we thought that at-bat was an important enough one to get him in the game. Obviously, he got the biggest hit of the night for us.”