With the win, the Marlins took a one-game lead over the Cardinals for the second National League Wild Card spot. The Giants loosened their grip on their NL West lead, falling into a first-place tie with the Dodgers, who beat the Phillies on Tuesday night.
Koehler stifled San Francisco, limiting it to two hits over seven innings. The reliable right-hander improved to 4-0 against NL West teams this season and has allowed two earned runs over his last 27 innings.
"Tom has really been saving us," said Marlins manager Don Mattingly. "He's basically been our best pitcher for the last month. We needed the innings tonight and he came through."
"He's got good stuff," Giants manager Bruce Bochy said of Koehler. "He throws hard. He had a good breaking ball today. Throwing quality strikes. He's been throwing well, and we knew that coming in. He's really been pitching well, and he was tough today."
Matt Moore may still be winless in two starts with the Giants, but he pitched well following a couple of first-inning runs. Stanton fisted his double to open the scoring and Marcell Ozuna tacked on another with an RBI groundout. Moore regrouped, however, allowing just the two runs over six innings while striking out seven.
"A quality outing is what I saw," Bochy said. "Two runs, six innings. He did a great job. The broken bat there, he makes a great pitch and breaks a bat. That led to two runs but he pitched great again."
MOMENTS THAT MATTERED Giant slayer: Koehler continued his mastery over the Giants, striking out six and walking three. Lifetime he is now 3-0 against San Francisco with a 1.38 ERA (26 innings, four earned runs). Tuesday's win was Koehler's first start against the Giants since 2014 when he also held them scoreless on four hits, striking out seven over seven innings in a 5-0 Miami win.
"I know I got my first win against them [in 2013], but that's really all I remember [about them]," Koehler said. "I don't know if there's anything to that." More »
Fresh out of hits: San Francisco's best shot to do any damage came down to the man who had seven hits just a night before. With two outs in the eighth, Angel Pagan singled and Brandon Belt walked to bring Brandon Crawford to the plate. The shortstop, all out of hits, flied out to left and finished the game 0-for-4. Crawford entered the game hitting a team-best .333 with runners in scoring position.
"Some days you're going to feel good and find some holes out there," Crawford said, "and some days you're not going to square the ball up or when you do it's going to go right at somebody. That's the game. That's baseball."
Breaking up is hard to do: Stanton nearly hit a broken-bat home run in the bottom of the first inning. The Marlins slugger settled for an RBI double, recording an exit velocity of 95.7 mph, according to Statcast™ -- above the league average of 89.2 mph. His blast short-hopped the fence in left field, scoring Dee Gordon for a 1-0 lead. Stanton was left holding a bat handle while the bulk of the bat sailed to the infield dirt between second and third base.
While Mattingly said he has seen a broken-bat homer, although he couldn't remember who hit it, he did acknowledge such a feat is certainly not the norm.
"It must be a real good bat," he quipped.
But really: Bochy joked about searching for a pill to help his club's offense while he was hospitalized Monday, but he may actually need to find one. San Francisco mustered three hits in the loss and finished 0-for-3 with runners in scoring position. On Monday night, the Giants finished 6-for-21 with men on and left 18 on base. Since July 1, they have hit a Major League-low .178 in those situations.
"We've got to find a way to get some runs. We've got a good lineup," Bochy said. "It's still not clicking. We had a heck of a game yesterday. Great comeback. But we're just not firing on all cylinders with that lineup. We will. We have some good hitters who are still trying to find it right now." More »
The Giants successfully challenged a pickoff attempt in the fifth inning. After Gordon walked to open the frame, Moore hummed a snap throw over to Belt, who applied the tag on Gordon's right arm. He was originally ruled safe but the call was overturned after a review.
WHAT'S NEXT Giants: In search of his first win since July 8, Jeff Samardzija (9-8, 4.40 ERA) takes the ball for San Francisco in the series finale with the Marlins on Wednesday at 9:10 a.m. PT. The right-hander is 4-1 with a 3.81 ERA in 16 career games (seven starts) against Miami.
Marlins: The Marlins go with David Phelps (5-5, 2.45 ERA) in the 12:10 p.m. ET series finale Wednesday with the Giants. In his only other start of the season, Phelps pitched shutout ball over 4 1/3 innings at Colorado on Friday, yielding four hits while striking out four and walking one, and received no decision.