Belt connected for his home run on the sixth pitch after Jhoulys Chacín relieved starter German Márquez, a 452-foot drive for his third career slam. Posey went deep four pitches later.
Márquez (1-3) allowed eight runs and six hits in two-third of an inning, an outing that raised his ERA from 4.13 to 6.21. He has lost to the Giants three times this season.
Colorado allowed double-digit runs in an inning for the seventh time and dropped to 1-6 against the Giants this year.
Belt and Posey finished with three hits each. Posey reached seven home runs in just 19 games played this season. “It was nice to have that cushion but I don’t think at any point did we feel comfortable to take our foot off the gas,” Giants manager Gabe Kapler said. “I thought Craw’s homer was as important as any big hit that we had in the first inning.”
Matt Wisler (1-2) retired Colorado's final five batters, Giants starter Aaron Sanchez allowed four runs and seven hits in four innings, including Raimel Tapia's fourth-inning grand slam, the third of his big league career.
Sanchez said the big early lead was “definitely nice” but he just focused on getting outs.
“You want to go out there and put up zeroes, that’s the main thing,” Sanchez said. “You don’t want to get caught in one of those back-and-forth, run-for-run games.” Alex Wood (3-0) was to start the second game for the Giants and Ryan Castellani was recalled from the alternate training site to make his season debut for the Rockies.
San Francisco sent 13 men to the plate and had eight hits in the first, its biggest inning since scoring 10 runs in the fourth of an 11-6 win over Pittsburgh on Sept. 7, 2008. It was the fifth time the Giants scored double digits in the first inning, the first since an 11-run frame against St. Louis on June 29, 1967. “You’ve got to give credit to the Giants,” Marquez said through an interpreter. “They’re a good-hitting team. I didn’t command the ball as well, and they took advantage of that.”
Giants: RHP Kevin Gausman was placed on the injured list after receiving a COVID-19 vaccination and experiencing symptoms. The team’s medical staff anticipated the after-effects will clear up in a day or two. ... C Joey Bart was recalled from the alternate training site. ... INF Tommy LaStella went on the 10-day IL, retroactive to Monday, because of a left hamstring strain. Manager Gabe Kapler estimated LaStella could be sidelined up to six weeks. ... INF Jason Vosler was recalled from the team’s alternate site.