SAN FRANCISCO — With one swing, Brandon Crawford sank the sinking Rockies even deeper in their slump. The Giants’ shortstop blasted a 365-foot moonshot homer to right field off Harrison Musgrave in the bottom of the ninth inning, a ball that just got over the wall to give San Francisco the 1-0 win and send Colorado to its fourth straight defeat. Crawford’s walk-off ended a pitching clinic Wednesday night at AT&T Park, when Giants veteran Madison Bumgarner and Rockies sophomore Kyle Freeland went toe-to-toe for seven innings of shutout baseball. Boxscore The southpaws then handed the game over to the bullpens in the eighth, and after Scott Oberg was able to produce four outs for the Rockies, Musgrave came on and immediately yielded the deciding homer to Crawford. Bumgarner opened the game by striking out DJ LeMahieu for his 1,500th career K, the fourth-fastest left-hander to reach the mark.