Dominic Brown hit two of Philadelphia's four solo homers in what was the Phillies' second straight win against the Red Sox.
Brown's first home run put the Phillies in front for good at 2-1 in the fourth and Erik Kratz followed with another blast in the inning.
Ryan Howard also homered for Philadelphia in the second and Brown added his second of the game and 13th of the season in the eighth.
The second of Brown's home runs turned out to be the game-winner when Papelbon gave up a run in the ninth while claiming his 11th save.
Papelbon put runners on first and second with two out before Jacoby Ellsbury doubled to right. Stephen Drew scored on the play, but Jonny Gomes was held at third and that was where he stayed when Daniel Nava grounded out to end the game.