SAN FRANCISCO -- Logan Webb has been a paragon of consistency for the Giants this season, but he couldn’t hide his frustration after being roughed up by the last-place Marlins.

Webb threw his glove against the dugout wall after giving up six runs over six innings in the Giants’ 7-5 loss in Sunday afternoon’s series finale at Oracle Park, which dropped the club two games below .500 entering the final month of the regular season.

“Everyone did the right thing except for me today,” Webb said. “I don’t feel good about it. I don’t think anybody in here feels good about it. I hope the guys don’t hang their heads too low because that was my bad.”

Webb entered Sunday with a 1.70 ERA over his last six starts and took a 2-0 lead into the fifth inning, but things quickly unraveled from there. With a runner on first and one out, Webb had a chance to start an inning-ending double play after fielding a comebacker from José Devers, but he made a poor throw to shortstop Tyler Fitzgerald, who had to lunge for the ball and tag Griffin Conine before firing to first base.

Devers easily beat out the throw to keep the inning alive for David Hensley, who followed with a two-out single to right field. Nick Fortes put the Marlins on the board with an RBI single, though the biggest blow came courtesy of Kyle Stowers, who crushed a 2-0 changeup from Webb out to right-center field for a three-run blast that put the Giants in a 4-2 hole.

“I’ve got to make that play,” Webb said of his poor throw. “I got exactly what I wanted: the first pitch right back to me. I made a couple of those plays earlier this year. It was just a bad throw and it leads to runs. I lost that game today. That was on me. It just sucks.”

San Francisco briefly regained a 5-4 lead after rallying for three runs in the bottom of the fifth, but Webb faltered again when he returned to the mound in the sixth, giving up a leadoff single to Jesús Sánchez, followed by a game-tying double to Jonah Bride. The Marlins went ahead for good on an RBI groundout from Otto Lopez, saddling Webb with his first loss since July 20. The six runs were the most the All-Star right-hander had allowed in a game since he gave up seven against the Blue Jays on July 10.

“It had all the makings of a really good game for us,” manager Bob Melvin said. “Logan was on his game, we scored a couple of runs early, which we were having a tough time doing. Then we don’t turn a double play, which gets us out of the inning with no runs. And then it just got away from him.

“This is probably as bad of a loss as we’ve had.”

The series loss to the Marlins represented the latest nadir for the Giants (68-70), whose playoff odds now stand at a season-low 0.3 percent, according to FanGraphs. They’ll likely face an uphill battle just to finish above .500 this year, as each of their final 24 games will come against teams with winning records.

“It’s always tough being in these positions, but it’s happened before where teams get hot and you can go on winning streaks,” Webb said. “Anything can happen. If you have the goal of coming in and trying to be the best version of yourself and try to win every day, I think good things happen.”

Sunday ended up being a day to forget for nearly every Giant except Mike Yastrzemski, who led off the bottom of the first inning with his 100th career home run. Yastrzemski smoked a misplaced fastball from Marlins starter Darren McCaughan over the right-field arcade to cement his spot in the century club -- no small feat considering the Giants’ outfielder broke into the Majors as a 28-year-old rookie in 2019.

Yastrzemski and his grandfather, Hall of Famer Carl Yastrzemski, became the fourth grandfather and grandson duo to each hit at least 100 homers in their MLB careers, joining former Giant David Bell and his grandfather Gus Bell, as well as brothers Aaron Boone and Bret Boone and their grandfather Ray Boone.

“It was huge,” Yastrzemski said. “I feel lucky to play long enough to even have a chance at that, let alone to do it. To tack on that many as a guy who started so late in his career in the big leagues, I’m feeling pretty humbled and very lucky today.”