The Yankees, with their second straight loss, fell seven games behind Boston in the battle for the American League's wild card berth.
An infield single by Kevin Youkilis and a triple by Jason Bay accounted for one run, after which Jed Lowrie and Jason Varitek drew walks to load the bases.
Alex Cora's sacrifice fly produced the second run of the inning and Coco Crisp singled in the third. Robertson then relieved Veras and gave up a single to Jacoby Ellsbury that again loaded the bases.
That brought up Pedroia, who hit a 2-0 pitch out to left-center field.
Boston starter Paul Byrd (9-11) got the win, giving up five hits and two runs in six innings. Byrd has a 6-1 mark since July 21.
The loss went to Sidney Ponson (7-5), who lasted just 4 2/3 innings while giving up seven hits and four runs.