On the fourth pitch of his at-bat, with the bases loaded, down to the team’s final out and facing one of the most fearsome closers in the game in Trevor Megill, Giants slugger Heliot Ramos did exactly what he needed to do with a 100-mile-per-hour fastball on Sunday. The 25-year-old laced a single to center, driving in his 54th and 55th runs of the season and giving San Francisco a lead it would not relinquish in a 4-3 come-from-behind victory in Milwaukee to clinch the three-game weekend series. San Francisco improved to 63-68, while Milwaukee fell to 81-50. The Giants are 6.5 games behind the Mets for the National League’s third and final wild-card spot.