Giants end Diamondbacks’ perfect season run in opener against them behind Gallen’s rough stretch

Arizona’s dominance over the San Francisco Giants this season finally ran out on Wednesday night at Chase Field, where the Diamondbacks’ run of eight straight wins against their rivals was stopped by a 6-4 Giants victory. It was the first time the matchup swung in San Francisco’s favor this year, and it immediately changed the emotional tone of what had been, for Arizona, a rare matchup edge.

The early picture suggested things could stay on Arizona’s script. In the first four innings, Zac Gallen allowed just one hit and managed to keep his command working, yielding no walks and recording a pair of strikeouts. Diamondbacks manager Torey Lovullo said afterward that Gallen was “really good for the early parts of this game,” adding that he was “driving his fastball into the right parts of the zone.”

But baseball does not reward precision forever when even a small miss becomes hittable. The release described Gallen as being in a stretch where mistakes, when they arrive, “cost dearly.” Although his control held early, two pitches that missed turned into home runs later in the game, and that is what shifted the scoreboard.

San Francisco struck first for a bigger cushion in the fifth inning. Heliot Ramos led off the frame by driving a sinker for a homer, and then Victor Bericoto added a two-run shot off a slider, stretching the Giants’ lead to 3-0. The damage highlighted the same theme the Diamondbacks were hoping to avoid, the notion that when Gallen’s location strays late, it can be punished quickly.

Arizona’s season-long sequence versus the Giants had been historic in its own way. The release noted the Diamondbacks’ 8-0 start against San Francisco marked the most consecutive wins to open a season against an opponent in franchise history, and they were “nearly able to pull this one out” as well. That context matters because it frames the loss less as a single bad night and more as a meaningful end to a longer storyline.

For Gallen, the aftermath sounded like frustration with the gap between putting pitches in the right places and what happens when they do not. He said that right now he feels like he is “on neither side of the coin,” and described how any mistake can turn into extra-base damage or, more specifically, leaving the ballpark. The quote is consistent with the sequence on Wednesday, where his early work kept damage to a minimum and later mistakes did not.

The Diamondbacks will now have to reset their approach for the next time they see the Giants. The release indicated there is one more series between the teams, a four-game set in San Francisco in August, giving both clubs a longer look at what the other side adjusted to when the matchup turned.

For now, Wednesday’s result is a reminder that even runs built on repetition can collapse in one outing. For Arizona, the question is how to manage the moments when its starter’s misses become flyballs and line drives instead of outs. For San Francisco, the test will be whether it can sustain the kind of adjustment that turned this matchup from an annual weakness into a short-term advantage.