The Red Sox won their second straight and stayed 1 ½ games in front of Texas for the top spot in the American League wild-card chase.
Victor Martinez singled in a run in the seventh to rally the Red Sox to a 3-3 tie and Bay hit a one-out home run in the eighth off Scott Linebrink (3-6) for what turned out to be the winning score.
Boston went on to add two more runs in the inning on a single by Nick Green, a double by Martinez and a single by Ellsbury. Jonathan Papelbon picked up his 30th save, the fourth straight season he has reached 30 saves.
Ellsbury had three hits in helping Boston win for the sixth time in eight games. He also stole his 55th base of the year to set a Red Sox single-season franchise record.
Manny Delcarmen (5-2) got the win by working the third inning in relief of Jon Lester.
Copyright 2009 by United Press International.