Photo: Giants pitcher Landon Roupp takes the loss after allowing 7 hits and 4 runs over 5 innings, despite recording 7 strikeouts in a game against the Arizona Diamondbacks at Oracle Park on Monday, May 25, 2026 (Jay Choi/SF Bay News Lab)

By Vince Cestone

SAN FRANCISCO — The Arizona Diamondbacks took advantage of sloppy defense from the San Francisco Giants, beating them 6-2 at Oracle Park on Monday afternoon.

After winning the series against the Chicago White Sox, the Giants came into Monday’s game with optimism. But a costly throwing error in the fifth inning by shortstop Willy Adames doomed San Francisco, as Arizona scored three times to take a two-run lead–a lead they would not give back.

The D-backs started the scoring in the third inning, when Gabriel Moreno hit a leadoff home run, his third of the year. With the Giants’ offense coming alive as of late, a one-run deficit did not seem insurmountable.

The Giants answered back in the bottom of the fourth inning. After a leadoff walk by Adames, Luis Arraez doubled to right field on a ball that just ticked off the glove of Corbin Carroll, putting runners at second and third with nobody out. The next batter, Casey Schmitt, struck out on a nasty breaking ball away from D-backs pitcher Merrill Kelly. But Rafael Devers hit a long double to right-center field, bringing in both runs and giving the Giants a short-lived 2-1 lead.

These would be the only runs that Kelly would surrender, as he threw seven innings, giving up just 4 hits and two walks. He struck out four batters. Kelly came into the game with a 4-3 record and a 5.71 ERA.

In the fifth inning, the D-backs went to work with the help of the Giants’ defense. Ninth-place hitter Tommy Troy led off the inning with a routine ground ball to shortstop, but Adames airmailed the throw to first, putting Troy at second base with nobody out. Second baseman Ketel Marte then doubled to left on a blooper that Schmitt misplayed. The ball got past Schmitt, allowing Marte to get to second and scoring Troy to tie the game. After Carroll hit a sacrifice fly to move Marte to third, Geraldo Perdomo singled, giving the D-backs a 3-2 lead. Arizona tacked on another run on a base hit by designated hitter Adrian Del Castillo.

Giants starter Landon Roupp deserved a better fate but struggled once again on Monday. Roupp went five innings, giving up seven hits, four runs (two earned), one walk, while striking out seven. Even though his defense let him down, Roupp was giving up hard contact to the D-Backs, especially in the fifth inning. In his first two innings, Roupp retired all six batters he faced, striking out three.

The Diamondbacks would tack on two insurance runs in the sixth inning against Giants reliever Joel Peguero. A leadoff walk by Moreno led to two runs. Marte, who has torched the Giants this year, hit a two-RBI single that gave Arizona a 6-2 lead. The D-Backs bullpen took it from there, pitching two scoreless innings.

The Giants fall to 22-32, while the D-Backs improve to 29-24. Arizona was hovering around .500 until they played the Giants, which is the get-right team for most contending teams these days.

Up next, the Giants will try to get back on track against the Diamondbacks as they play Game 2 of the series. The Giants are still looking for their first win against Arizona in 2026, as they are now 0-4 against them. Arizona will send Eduardo Rodriguez (4-1, 2.24 ERA) to the mound against the Giants’ Tyler Mahle (1-6, 6.10 ERA). Game time is at 6:45 PM.

In order to get back into the playoff race, the Giants need to sweep some series, and they already missed a golden opportunity to do so at home. Their next chance will be against the Colorado Rockies this weekend, but given the way the Giants are playing, sloppy defense will not play well in Colorado.