PHILADELPHIA -- Logan Webb couldn’t catch a break.

The Giants right-hander thought he recorded the final out of the fourth inning when he got J.T. Realmuto to hit a slow roller up the middle, but the Phillies catcher managed to beat it out for an infield single, which was confirmed following a successful challenge by Philadelphia.

After returning to the mound, Webb got the next batter, Bryce Harper, to send a sinking liner to left field, but Michael Conforto appeared to lose the ball in the lights at the last second, keeping the inning alive for the Phillies.

Webb finally got the elusive third out by fanning Alec Bohm to leave both runners stranded, but the misfortune added up to another uncharacteristically short night for San Francisco’s ace.

Webb gave up five runs (four earned) on six hits -- including a three-run homer to Harper -- and two walks over four innings as the Giants lost their third straight game to the Phillies, 5-4, on Sunday night at Citizens Bank Park.

After logging a 2.33 ERA over his first six starts of the year, Webb has now yielded nine runs over 7 2/3 innings in his past two outings, marking the first time he’s been unable to complete five innings in back-to-back starts since August 2022.

“As the guy who they look at as the No. 1 pitcher on the team, I’ve got to be better than that,” Webb said. “The last two, I think, have not been very good. I started the road trip off with a pretty bad game. I kind of kept that going today.

“It’s something I might have to look at. I felt good today. I thought my pitches were doing the right stuff. I just didn’t get the results.”

The Giants (15-20) have lost five of their first six games on this road trip to Boston and Philadelphia, dropping a season-high five games below .500. They’ll try to avoid being swept by the Phillies on Monday, when right-hander and No. 7 prospect Mason Black is set to make his Major League debut and start opposite one-time Giants prospect Zack Wheeler.

“It’s a lot of things going on,” manager Bob Melvin said of San Francisco’s recent woes. “We’re not pitching well. We’re not swinging the bats well. We’re not swinging it well with runners in scoring position. Our defense hasn’t been good lately, either.”

The Giants also gave the Phillies an extra out in the second, when Bohm hit a routine grounder to shortstop Nick Ahmed, who airmailed his throw to first base after appearing to stumble on the infield dirt. The ball ended up landing out of play, resulting in a two-base error for the typically sure-handed Ahmed.

Bohm later scored on a two-out infield single by Edmundo Sosa, who shattered his bat on a 2-2 sinker and sent splinters flying toward the mound, hampering Webb’s ability to field the 48.6 mph comebacker. Second baseman Thairo Estrada came running in to retrieve the ball, but Sosa managed to beat out his throw to first, tying the game at 1.

The Phillies grinded out long at-bats against Webb and got his pitch count up early, with Kyle Schwarber working a seven-pitch walk that set the table for a four-run rally in the third. Harper delivered the big blow, driving a changeup at the bottom of the zone out to right-center field for a three-run homer that put the Phillies ahead for good.

“It was on the bottom rail,” Webb said. “That guy gets paid, however many millions he’s getting paid, to hit home runs, and he did it there. I thought I threw a good pitch. He’s just a very good baseball player, and he was the better player on that pitch.”

Webb threw 98 pitches and departed with the Giants trailing, 5-1, though they managed to pull within two on Estrada’s two-run blast off Taijuan Walker in the seventh. Newly promoted catcher Jakson Reetz added his first career Major League home run -- a ninth-inning solo shot that finally snapped the Giants’ streak of nine consecutive games without scoring more than three runs -- but it was too little, too late for San Francisco.

“It feels great, but I just wanted to try to help the team win,” Reetz said. “I guess the most important thing right now is we’ve just got to get back to winning ball.”