Sheets (4-1) yielded one run on seven hits over 7 1/3 innings while issuing a single walk. The right-hander rebounded from his first loss since joining the Braves in his previous outing, a 4-2 loss to Miami Wednesday.
Jason Heyward added a solo shot for Atlanta, which maintained its tie with Pittsburgh for the National League wild card lead.
Vance Worley (6-7) was touched for four runs on six hits over just 3 2/3 innings for the Phillies, who dropped the opener of a three-game series.
John Mayberry homered for the Phillies.