SAN FRANCISCO -- Kyle Harrison could be forgiven for looking rusty in his return from the injured list at Cleveland last week.

Desperate to fortify their decimated rotation, the Giants decided to send Harrison to the mound without the benefit of a rehab assignment, a move that seemed questionable after the 22-year-old left-hander couldn’t get out of the fourth inning in his first start in nearly a month.

Harrison looked much sharper in his second outing back from the IL, tossing 5 1/3 innings of one-run ball to help pave the way for the Giants’ 7-1 series-opening win against the Twins at Oracle Park on Friday night.

Brett Wisely went 3-for-3 with two RBIs and fell a home run short of a cycle, drawing a walk in his final plate appearance against left-hander Kody Funderburk in the eighth inning to cap his productive day at the plate. Jorge Soler and Heliot Ramos also delivered multihit efforts to help back Harrison, who allowed five hits while walking one and striking out three.

The Giants have won 10 of Harrison’s last 13 starts, improving to 11-5 when the De La Salle product takes the mound this year.

Harrison has been one of the most fastball-reliant starters in the Majors this year, but he mixed in more changeups to try to neutralize the Twins’ right-handed-heavy lineup, which entered Friday with an MLB-high .802 OPS against lefties this year. Twenty-nine of his 83 pitches were changeups (35 percentage), a notable jump from his average usage (19.9 percent) this year.

“I felt great,” said Harrison, who ended the first half with a 4.08 ERA over 16 starts. “I was able to kind of slow down and really settle in. I was happy with my offspeed, for the most part. The changeup is still getting there, but I was really happy with the slider and able to land it. I didn’t do too well on first-pitch strikes, that’s something I need to get better at, but I was able to battle my way back and go as far as I can.”

Harrison opened his outing with five scoreless innings, though he got some assists from his defense, as Michael Conforto made a jumping catch at the left-field wall to help strand a runner in the second and Ramos laid out to snag Carlos Santana’s sinking liner to shallow center in the fourth.

“That’s a team that really hits left-handed pitching,” manager Bob Melvin said. “That’s a tough group to navigate through. … Really, it was the fastball quality at the top of the zone and mixing his changeup and his breaking ball in and throwing some for strikes, too.”

The Twins threatened in the fifth after Ryan Jeffers singled and Brooks Lee walked, but Harrison escaped the jam by coaxing a popup from Matt Wallner and striking out Christian Vásquez and Manuel Margot swinging. Still, he couldn’t avoid damage in the sixth, as he surrendered a leadoff single to almost-Giant Carlos Correa, followed by a double to Santana.

Wisely made a leaping grab at shortstop to rob Byron Buxton and help Harrison record the first out of the inning, but Melvin decided to bring in Ryan Walker to face Willi Castro, who knocked in the Twins’ lone run with an RBI groundout.

“He has good stuff,” Minnesota manager Rocco Baldelli said. “He’s got that good riding fastball. I don’t know if it’s truly riding, but the slot that he comes from, he can pitch up in the zone. It took our guys a little bit to kind of dial him in. They haven’t seen him before and he went to his breaking ball and changeup enough. He did a good job. … He’s a good-looking young arm.”

Harrison bested another former Bay Area prep star in Twins right-hander Joe Ryan, an alum of what was then Sir Francis Drake High School, who was tagged for five runs on six hits over 5 1/3 innings in front of his hometown crowd.

The Giants jumped on Ryan early, with Soler leading off the bottom of the first with a liner to right that skipped past a diving Wallner and rolled to the wall for a triple. Soler scored on a sacrifice fly by LaMonte Wade Jr. to put the Giants on the board before the club added another pair of runs on RBI hits by Mike Yastrzemski and Wisely in the second.

Wisely also tripled and scored in the fifth, marking the first time the Giants have recorded two triples in a game since June 9, 2022, against the Rockies.