LOS ANGELES -- When he stepped up to the plate to take his first at-bat for the Giants in over two weeks, Buster Posey drew his customary round of boos from the fans at Dodger Stadium. It didn’t take long for him to silence the crowd, though.

In his first at-bat since returning from the injured list, Posey drilled a two-run home run that helped ignite the Giants’ 7-2 series-opening win over the Dodgers on Monday night.

“I was wondering how that first at-bat was going to go with that long layoff,” manager Gabe Kapler said of Posey, who missed seven games with a left thumb contusion. “Obviously, we weren’t able to get him into any sim games or anything like that. Just to see him come out, step up to the plate and hit a big home run for us was incredibly impressive.”

Posey and Wilmer Flores launched back-to-back home runs off Tony Gonsolin to stake the Giants to a 3-0 lead in the first inning, but the Dodgers pulled within one after Max Muncy and Justin Turner went back-to-back off All-Star right-hander Kevin Gausman in the bottom half of the inning.

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The Giants broke the game open with a four-run seventh that was highlighted by a two-run double from Thairo Estrada, who is filling in at shortstop for the injured Brandon Crawford.

Monday’s victory served as a microcosm for two major themes that have helped drive much of the Giants’ success this year: resurgent campaigns from veterans like Posey and key contributions from bench players like Estrada, who have stepped in to plug holes when needed.

With the win, the Giants improved to 59-34 overall and 4-6 against the Dodgers, who fell two games out of first place in the tightly contested National League West. The archrivals are currently in the midst of a stretch in which they’ll face each other seven times in 11 days, heightening the stakes of these July showdowns.

“It’s a really well-balanced team,” Dodgers manager Dave Roberts said of the Giants. “They can pitch, they catch the baseball, they take professional at-bats and they’ve played really well all year long. They’ve earned that right to have the best record in baseball. We’ve got our hands full. It’s going to be a fun series.”

Gausman, who was pitching for the first time in eight days, grinded through three strenuous innings in his shortest start of the season, but relievers Zack Littell, Jarlín García, Dominic Leone, Jay Jackson and Jake McGee combined to deliver six shutout innings to lock down the win for the Giants.

“That’s obviously a gutsy win for us,” Littell said. “We joke down there, but we probably have the most bang for your buck bullpen in the entire league.”

Gausman allowed two runs on three hits while walking three and striking out five, but the Dodgers forced him to throw 80 pitches and whiffed on only eight of his offerings. While his delivery was out of sync and he struggled to replicate the normal shape of his devastating splitter, Gausman managed to limit the damage by holding the Dodgers 0-for-5 with runners in scoring position.

Gausman was initially slated to pitch on Friday at St. Louis, but the Giants placed him on the family medical emergency list after his wife, Taylor, was hospitalized due to complications with her pregnancy over the weekend.

“It’s obviously unexpected when you have Gausman on the mound, although he’s been dealing with a lot between the travel, the layoff, the family needing his support,” Kapler said. “I think it was a pretty tall order. We always expect Kevin to go deep into the game, but we understood that he was dealing with some things.”

Still, the Giants’ bullpen carried the load the rest of the way, issuing only one walk and allowing only one hit -- a ninth-inning single by AJ Pollock off McGee. San Francisco’s relievers now have a collective 3.27 ERA this season, the third-lowest mark in the Majors behind only the Padres and the Rays.

“Oh man, they’ve been unbelievable,” Gausman said. “I mean, they have been all year, but they really picked me up right there. To come in and shut down that lineup, especially the way that they were swinging it against me, to come in and just pound the strike zone, that was the biggest thing. I think they only walked maybe one or two guys. To do that against that lineup was really impressive. That was the reason why we won the game.”