SAN FRANCISCO >> Rafael Devers never harbored any concerns about hitting in San Francisco. In Devers’ mind, he didn’t need to change anything about his approach. The baseball, after all, is still the same.

“I know that I’m a power hitter,” Devers said through team interpreter Erwin Higueros on Friday. “If I hit the ball good, I know it will go out of any ballpark.”

Any ballpark, of course, includes Oracle Park. On Saturday afternoon at China Basin, Devers proved his power will play in the Bay against, appropriately enough, a team that knows his power all too well.

With his first homer as a Giant, a two-run, opposite-field shot, Devers powered San Francisco to a 3-2 win over the Boston Red Sox — the only major-league team Devers had known for more than a decade. In Boston, Devers blossomed into one of baseball’s best players. In San Francisco, the Red Sox can only watch their former star from afar.

“I’m really happy that I was able to contribute to the win,” Devers said. “Hopefully (I can) continue to contribute, give my 100 percent and hopefully get more wins.”

Devers downplayed the significance of the homer, saying it was “nothing more special than any other home run that I’ve hit.” Considering what’s unfolded over the last week, there will be few homers in Devers’ career that will match the magnitude of his first with the orange and black.

“It kind of feels almost like a little weight fell off his shoulders when he hit that ball,” said starter Landen Roupp. “You could just see it. We expect many more from him in that area. Really excited to have him on the team, and I think he’s going to be a huge help.”

Devers went hitless over five at-bats in his first game against Boston in Friday’s 7-5 loss, then grounded out in his first plate appearance of Saturday’s game. When Devers stepped to the plate in the bottom of third, he had only recorded three hits in 17 at-bats with his new team.

Manager Bob Melvin never got the impression that Devers was pressing even amidst all that had happened in the last week. If Devers was pressing, Melvin said “it certainly isn’t evident to me.” In his seventh at-bat against his former team, Devers finally met the moment.

With Andrew Knizner on first, the Red Sox’s Brayan Bello began his battle against Devers with a 95.7 mph four-seam outside fastball for a called strike. Bello, who played alongside Devers for four seasons, tried going back to that well. Devers sent the offering over the left-field fence for this 16th home run of the season, sending the announce attendance of 39,027 into a frenzy.

“He’s my brother out there,” Devers said of Bello, “but we know that once we cross that line, we’re competing with each other. Whoever wins, wins. It was us this time.”

Added Melvin: “That’s kind of typical him, too. Let it travel, catch it late and block it out to left field. He’s done it so many times in Boston, and this park kind of plays that way to lefties as well. To get that one off his back, (he feels) good about that. Obviously, be incredibly impactful in the outcome of the game. Now, he can settle in and do his thing.”

Along with their new acquisition, the Giants saw homegrown talent contribute to Saturday’s win.

Heliot Ramos served as the appetizer to Devers with a solo homer, his 13th of the season, and Roupp turned in his seventh quality start of the year with seven strikeouts over six scoreless innings. For Roupp, Saturday’s outing allowed him to put behind one of the worst games of his career, a start where he allowed six runs and recorded just five outs against the Los Angeles Dodgers.

Roupp normally watches film of his previous start as he’s preparing for the next start, but the 26-year-old didn’t bother reviewing his outing against the Dodgers. Given how poorly he pitched, Roupp didn’t believe a film session was necessary. The mindset was simple: move on and compete.

“He’s a competitor,” Melvin said of Roupp. “It’s not like he backs off or he’s timid or anything on the mound. It’s just the opposite. Sometimes, it’s too much confidence in what he’s doing, if there’s such a thing. I didn’t worry about him worrying about it and lacking confidence when he took the mound today. He was just looking forward to getting back out there.”

Roupp earned his fifth win of the season but almost got stuck with a no-decision when Camilo Doval nearly blew a save in the ninth inning.

Doval entered the ballgame with the Giants leading by three runs but the Red Sox began the frame with three straight hits. Wilyer Abreu’s RBI single shrunk San Francisco’s lead to two runs, then a throwing error by Knizner allowed another run to score and whittled the Giants’ advantage to 3-2. Boston put a runner on third base with two outs, but Doval shut the door and secured the win.

The last five days have provided Devers with an opportunity to become acclimated with his new stomping grounds. He appreciates the love from his new fans, and after thrilling the Oracle Park crowd with the first of many homers, Devers made sure to send love right back to his old supporters.

“As we know, San Francisco and Boston have the greatest fans,” Devers said. “Now that I’m on this side, I really do appreciate how they have received me. But let’s not forget how good the fans in Boston are, too.”