Matt Chapman hit a grand slam to help the San Francisco Giants beat the lowly Colorado Rockies 6-3 on Saturday. Chapman connected against Jake Bird (0-1) with one out in the sixth, capping a five-run inning after the Rockies scored three times in the top of the frame.

With the bases still full, the Rockies’ Jake Bird left a sinker right over the heart of the plate. Chapman sent it 402 feet into the Rockies’ bullpen, flipping a one-run deficit into a three-run lead — a lead they’d never lose as Camilo Doval, Erik Miller and Ryan Walker pitched three scoreless innings.

Walks will haunt, and leadoff walks will haunt absolutely. And for bad teams like the Rockies, walks kill any chance of winning.