Jorge Alfaro got some timely advice from a teammate, and he put it to good use. Alfaro hit a massive home run off Madison Bumgarner, Miguel Rojas doubled in the go-ahead run in the top of the eighth inning, and rookie Robert Dugger pitched 6 1/3 solid innings as the Miami Marlins beat the San Francisco Giants 4-2 on Saturday night. Rojas, who played for the Los Angeles Dodgers in 2014 and is familiar with the challenging hitting conditions in San Francisco's waterfront ballpark, advised the Marlins slugging catcher to ''just swing under the ball.