Like many of the Giants’ veteran players, Johnny Cueto opened the 2021 season looking like his vintage self, logging a 1.80 ERA over his first three starts before landing on the injured list with a Grade 1 lat strain.

After missing nearly a month, Cueto rejoined the Giants’ rotation on Sunday, though his return didn’t unfold as he had envisioned. The 35-year-old right-hander was charged with the loss after allowing five runs over three innings in the Giants’ 11-1 defeat against the Padres on Mother’s Day at Oracle Park.

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Cueto surrendered a pair of long two-run home runs to Jake Cronenworth and Fernando Tatis Jr. in the second inning, putting the Giants in an early 4-0 hole. The Padres added another run off Cueto on Wil Myers’ RBI single in the third and later broke the game open with a four-run eighth to avoid a three-game sweep and pull within 1 1/2 games of the first-place Giants in the National League West.

After outscoring the Padres 12-5 in the first two games of the series, the Giants were limited to eight hits by right-hander Chris Paddack and four San Diego relievers. The Giants were held scoreless until the eighth, when Brandon Belt walked, advanced to third on Evan Longoria’s 400th career double and scored on Brandon Crawford’s sacrifice fly.

Giants outfielder Darin Ruf also achieved a notable milestone, making his first career pitching appearance in the ninth. Ruf threw 21 pitches, topping out at 77.5 mph, and gave up a pair of runs on an RBI double by Jorge Mateo and a sacrifice fly by Ha-Seong Kim. He became the first Giants position player to pitch since former catcher Tyler Heineman on Aug. 16, 2020, against the A’s.

“This is kind of the peripheral benefit or the silver lining,” manager Gabe Kapler said. “You get some life experience for Darin Ruf, a story for him to tell. I do think it can kind of lighten the mood in the dugout after a tough stretch of innings, to say the least. The reason you do it is to save an inning for your bullpen, but there is some peripheral benefit.”

Cueto worked around a leadoff hit to post a scoreless first inning, but he dealt with tough luck after Myers reached on an infield single to start the second. Myers tapped a ball slowly down the third-base line, but it was declared fair after hitting the bag, setting up Cronenworth’s two-run blast into McCovey Cove.

Cronenworth crushed a backdoor slider from Cueto 445 feet out to right field, securing the third splash hit by an opponent this year.

“I think early on there were some balls that got through,” Kapler said. “I think sometimes that can spiral a little bit. There were some mistakes as well, but we saw a healthy pitcher, and we saw a pitcher who had life on his stuff.”

Cueto continued to give up loud contact for the remainder of the inning, yielding a double to Victor Caratini, followed by a 454-foot shot to Tatis, who hammered a misplaced slider out to left-center field.

“I made a couple of bad pitches,” Cueto said in Spanish. “I hung a pitch to Tatis. Same with the second baseman [Cronenworth]. I threw that one down and in, but those things happen. It’s part of the game.”

The Padres extended their lead to 5-0 after Cueto gave up three consecutive hits to start the third. Cronenworth then walked to load the bases, but Cueto avoided further damage with a huge assist from center fielder Steven Duggar, who made a diving catch on a sinking liner from Paddack for the final out of the inning.

Cueto departed after giving up eight hits and throwing 64 pitches in his shortest outing of the year, but he said he felt good and is now more confident that he’s past the back issue.

Cueto fell to 0-3 with a 7.85 ERA (16 earned runs over 18 1/3 innings) over his last four starts against San Diego, but he won’t have to worry about drawing another tough assignment against San Francisco’s division foe for a while, as the Giants and Padres won’t meet again until Sept. 13.