Joe Panik hit a go-ahead sacrifice fly in the seventh inning and the San Francisco Giants snapped a three-game losing streak by beating the Washington Nationals 5-3 on Saturday. Anthony Rendon hit a two-run homer in the third for the Nationals, who couldn't protect an early 3-0 lead hours after acquiring All-Star closer Mark Melancon from the Pittsburgh Pirates to replace the struggling Jonathan Papelbon. San Francisco, which is beginning to get healthy, loaded the bases against former Giants reliever Yusmeiro Petit (3-2) with one out in the seventh to bring up Panik.