SAN FRANCISCO -- The Giants pulled off back-to-back late-inning comebacks to complete a three-game sweep of the Rockies earlier this week, but their rally magic dried up after returning home to face the Cubs on Friday night at Oracle Park.

Former Cub Joc Pederson matched a career high with four hits against his old team, but the rest of San Francisco’s lineup couldn’t get much going against Marcus Stroman, who outdueled fellow right-hander Anthony DeSclafani en route to handing the Giants a 3-2 loss in the opening game of this three-game series.

Stroman earned his fifth consecutive win for the Cubs after holding the Giants to two runs on six hits over 6 2/3 innings, raising his ERA to 2.42 but remaining the second-best mark in the National League. Thairo Estrada put the Giants on the board with a two-out RBI double in the third, but they didn’t score again until Pederson beat out an infield single that knocked in Brandon Crawford from third in the seventh.

“I think it’s just the continued competitiveness that comes out of Marcus every time he takes the mound,” manager Gabe Kapler said. “It’s pretty impressive. Excellent command, control of a sinker-slider combination that can be really challenging, particularly for right-handed hitters. Some early solid contact between Joc and [Mike Yastrzemski]. A hard ground ball from Estrada. Just not enough to really do any damage.”

“I think it’s just the continued competitiveness that comes out of Marcus every time he takes the mound,” manager Gabe Kapler said. “It’s pretty impressive. Excellent command, control of a sinker-slider combination that can be really challenging, particularly for right-handed hitters. Some early solid contact between Joc and [Mike Yastrzemski]. A hard ground ball from Estrada. Just not enough to really do any damage.”

DeSclafani rebounded from a shaky start against the Orioles last week and carried a shutout bid into the seventh inning, but he departed with a pair of runners on and no outs after giving up a leadoff single to Seiya Suzuki and a walk to Ian Happ.

With back-end relievers Camilo Doval, Taylor Rogers and Tyler Rogers down after working back-to-back games in Colorado and left-hander Scott Alexander unavailable due to a hamstring issue, Kapler opted to bring in rookie Ryan Walker, who ultimately couldn’t preserve the Giants’ one-run lead.

The 27-year-old right-hander hit Matt Mervis to load the bases with one out before surrendering a go-ahead, two-run single to pinch-hitter Nico Hoerner. Walker then walked Christopher Morel to re-load the bases for Tucker Barnhart, who lined an RBI single that extended the Cubs’ lead to 3-1.

DeSclafani was charged with two runs on three hits over six-plus innings, though he also issued a season-high four walks in the 93-pitch effort.

“I’m just trying to work on some mechanical stuff in between starts and kind of still felt a little out of whack,” DeSclafani said. “Walks are not ideal. It’s tough. I’ve got to stop walking so many guys, but for the most part, I thought I did a fine job competing.”

DeSclafani felt he had gotten too slider-happy after giving up a season-high six runs (five earned) over three innings in his last start against Baltimore, so he made some tweaks to his pitch usage against the Cubs. He still relied primarily on his slider (41%), but he also threw more four-seam fastballs (19%) in addition to his steady diet of sinkers (23%).

“[Catcher Patrick] Bailey was inputting some pitches during the game and we were kind of going back and forth calling the game,” DeSclafani said. “I think we all agreed that I needed to input the fastball more, and he helped do that. I thought it was a good usage of the heater and a good mix overall.”

San Francisco was without one of its best hitters for most of the night, as third baseman J.D. Davis was scratched about an hour before first pitch with right hip tightness. Rookie Casey Schmitt started at third in Davis’ place, but he continued to slump at the plate, going 0-for-3 to slip into a 3-for-28 skid over the last eight games.

Davis pinch-hit for Bailey to lead off the ninth, but he flied out against right-hander Adbert Alzolay, who then struck out Crawford and Wilmer Flores to end the game.

“You’re going to have some games where you come out and you’re not swinging the bats the way you want to, putting up crooked numbers like we were doing in Colorado,” Kapler said. “You have one inning that doesn’t go well and you lose a baseball game. You quickly turn the page and get ready for tomorrow.”