SAN FRANCISCO -- At the beginning of the month, it looked like Keaton Winn would get only a brief look in the Giants’ starting rotation.

Winn opened the season as the club’s fifth starter, but he seemed to be in line for a shift to the bullpen once Alex Cobb completed his rehab from offseason hip surgery. But a move that once felt imminent was officially pushed back on Saturday, when the Giants transferred Cobb to the 60-day injured list after he experienced some minor setbacks with his right elbow and shoulder.

Cobb won’t be eligible to return until May 27, so the Giants will be counting on Winn to hold down that rotation spot until then. The 26-year-old rookie certainly seems to be up to the task.

Winn fired six-plus innings of one-run ball to lead the Giants to a 5-2 series-opening win over the Mets on Monday night at Oracle Park.

Winn faced the minimum over his first four innings and permitted only four hits -- including a fifth-inning solo shot to Pete Alonso -- while striking out six and walking one in his best outing of the season.

The Giants have struggled to support Winn early this year, scoring only seven runs in his first four starts, but they finally allowed him to pitch with a bit of cushion on Monday.

Michael Conforto, a former Met, launched a solo home run, and Nick Ahmed and Matt Chapman delivered RBI hits to back Winn, who improved to 2-3 with a 3.54 ERA on the season.

“I’m always impressed every time he goes out there,” Conforto said. “Just the stuff he has, it’s elite stuff. The splitter is for real. It’s really hard to get the ball in the air against him. It fits kind of what we like to do as far as pounding the zone and getting ground balls. He’s also got the stuff to strike guys out. Getting him a lead and letting him settle in a little bit is going to help. But we’re always confident every time he’s going out there on the bump.”

Winn needed only 79 pitches to cruise through six innings and got the chance to pitch into the seventh for the first time in his career, but he was removed after giving up a leadoff single to Starling Marte and a walk to Francisco Lindor.

“I think the last time I pitched into the seventh was in A-ball in 2019,” said Winn, who departed after throwing 87 pitches. “So it was nice to go back out there. I wish I could have gotten an out in the seventh inning, but I gave up a hit and was just trying to be too perfect. It’s a learning moment, for sure.”

Ryan Walker relieved Winn and retired Alonso, Brett Baty and DJ Stewart in order to leave the two inherited runners stranded and protect the Giants’ 5-1 lead. Tyler Rogers delivered a scoreless eighth before giving way to Camilo Doval, who entered the game in a non-save situation but still debuted his dramatic new entrance, which featured new programmable spotlights that traced the All-Star closer’s path from the bullpen to the mound.

Doval heightened the ninth-inning drama by giving up a run and issuing a pair of walks to bring the tying run to the plate, but he managed to coax a groundout from Stewart to end the game.

“I knew they were going to do the light show, but I didn’t think it was going to be like that,” Doval said in Spanish. “It looked like a movie.”

“That was so sick,” Winn said. “I saw it on the TV, and I was like, ‘Oh my gosh, I wish I was outside for this.’ That would have been cool to see in person. Hopefully they do that more often. It was so cool.”

Winn shone brightly even without the spotlights, leaning on his fastball-splitter combination to neutralize the Mets’ patient lineup. Opposing hitters entered Monday batting only .182 (6-for-33) with a .273 slugging percentage off Winn’s signature splitter, though Alonso managed to hit one out to left field for his solo homer.

Still, that ended up being the lone blemish against Winn, whose 42.8% splitter usage leads Major League starters this season.

"He was throwing it for strikes, and a lot of times, it looked just like his fastball,” Alonso said. “He throws it at the same lane, and it's got nice late action on it. He got guys to swing on top of it, hit ground balls, or swing over it because he would execute underneath the zone. He did a great job tunneling tonight."