SAN FRANCISCO — Mike Yastrzemski couldn’t have scripted a better Fenway Park debut when the Giants last visited Boston in 2019.

He caught the first pitch from his Hall of Fame grandfather, Carl, and went on to homer into the center-field bleachers, marking the first time a Yastrzemski had gone deep at Fenway since July 31, 1983.

Yastrzemski’s second homecoming isn’t expected to generate quite as much buzz as his first, though the 33-year-old right fielder could continue to make some noise now that he seems to be heating up at the right time.

Yastrzemski and Thairo Estrada delivered back-to-back home runs in the third inning to power the Giants to a 3-2 win over the Pirates and clinch a series victory on Sunday afternoon at Oracle Park.

Estrada opened the scoring by driving a first-pitch slider from right-hander Jared Jones out to left-center field for his fourth home run of the year. Yastrzemski made it 2-0 by sending a 98.4 mph fastball out to dead center for his second blast of 2024. It was the first time the Giants had gone back-to-back since Sept. 8, 2023, when Wilmer Flores, Mitch Haniger and J.D. Davis launched three consecutive homers against the Rockies.

“When you have a guy like him hitting in the eight-hole, you know that you have a chance to potentially score every inning,” manager Bob Melvin said of Yastrzemski. “But he’s heating up now to where he’s swinging the bat really well. We have a great feeling every time he’s up there. Their guy was really good. We got him on the run a little bit, but we knew coming in that was going to be a tough customer to score some runs off of. When we get back-to-back homers, it feels like more than just two runs.”

LaMonte Wade Jr. added a sacrifice fly to turn over a three-run lead to rookie right-hander Keaton Winn, who made sure it held up by limiting the Pirates to one run over six strong innings. Winn allowed only three hits while walking one and striking out five, improving to 3-3 with a 3.18 ERA over six starts this year.

Yastrzemski batted only .121 (4-for-33) with 12 strikeouts and no extra-base hits over his first 13 games, but he got back on track over the Giants’ longest homestand of the year, going 9-for-22 (.409) with two homers and eight RBIs across eight games.

Melvin said it was only a matter of time before Yastrzemski began to settle in, as he was slowed by a left shoulder impingement during Spring Training and then missed three games after he went on paternity leave during the first week of the regular season.

The lack of consistent at-bats contributed to Yastrzemski’s slow start, though he also felt he compounded the issue by beginning to press at the plate when he wasn’t getting the results he wanted.

“Not a great place mentally in terms of not getting off to the start I wanted,” Yastrzemski said. “Pressing, trying to do too much. Sometimes it takes just a little bit of time to let that go. I finally let it go and focused on the things that I needed instead of the scoreboard and started having a lot better at-bats.”

Some fans have called for the Giants to promote young outfielders like Heliot Ramos and Luis Matos amid the ongoing struggles of Yastrzemski and Austin Slater, his platoon partner in right field, but Melvin has stuck with the veterans and continued to express confidence in their ability to contribute to the offense moving forward.

“I’ve got to thank BoMel and all the hitting coaches for sticking with it because they trusted it and knew that I’d be able to eventually trust my process and get back to where I needed to be,” Yastrzemski said. “It’s still not perfect. No one’s ever going to be perfect. But it’s a work in progress, and at least it’s a more comfortable place to continue working from.”

Yastrzemski’s recent surge has helped put him in a better frame of mind as he returns to Boston for the Giants’ series opener against the Red Sox on Tuesday night. He isn’t sure if his grandpa will be able to make it out to Fenway this time around, but he’s still looking forward to catching up with plenty of other friends and family members while he’s in town.

“It’ll be fun,” Yastrzemski said. “I’m excited to get back. Anytime you can play at Fenway, regardless of whoever you are, it’s a great atmosphere, and it’s always special.”