Sanford had the best outing from a starting pitcher this homestand, giving up just one earned run on four hits over six innings.
"This is exactly what we were looking for and waiting for (out of a starting pitcher)," manager Lipso Nava said.
Sanford moved into the starting rotation for the first time after posting a 1.74 ERA in five relief appearances.
"I love starting," Sanford said. "I like to be the one to set the tone early and mix up my pitches and pound the middle half of the plate and open things up for the guys with the strong arms in the bullpen."
Those arms let Sanford down after he left in the top of the seventh with a 3-1 lead.
Edwin Escobar, who lost his place in the starting rotation to Sanford after two rocky outings, came on in relief and let three runs cross the plate on two walks, a single and a wild pitch. Escobar suffered his third loss of the season on his 19th birthday.
Carlos Willoughby and Adam Duvall gave the GreenJackets an early lead in the first inning. Willoughby reached on his fifth walk in two nights and stole second base. After Raynor Campbell struck out, Duvall extended his hitting streak to 10 games and drove in Willoughby with a single to left field.
Delmarva used a Josh Mazzola error to tie the game at 1 in the top of the fifth, but the GreenJackets regained the lead thanks to a Ydwin Villegas sacrifice fly and a Mazzola walk with the bases loaded in the bottom of the inning.
Sanford finished the sixth inning on just 64 pitches and handed the game over to the bullpen in the seventh. Escobar and Drew Bowlin allowed four runs in two innings, highlighted by a Kipp Schutz triple in the eighth.
Augusta's Rafael Rodriguez went 3 for 4 with a run-scoring double in the bottom of the eighth to start another late rally. The GreenJackets put the potential game-tying and winning runs on base in the ninth only to end the game on a line drive double play.
Delmarva starter Tim Berry gave up three earned runs on four hits and walked two before he was pulled with one out in the fifth. Reliever Jarret Martin (1-1) got the win after allowing one run on three hits in three innings.