The Padres top prospect allowed one hit over five scoreless innings Wednesday as the San Antonio Missions blanked the Frisco RoughRiders, 1-0.
Being kept on a strict pitch count through the end of the season, Kelly (10-3) needed only 48 to get through five innings. He allowed only two baserunners, hitting Mike Bianucci leading off the second and giving up a one-out single to Renny Osuna in the third.
In his last start on Friday, Kelly scattered 12 hits and yielded two runs over five innings against Midland.
"It felt good to get back out there after my last start," he said.
The 21-year-old right-hander has won four straight and six of his last seven starts. He joined Arkansas' Garrett Richards as the only 10-game winners in the Double-A Texas League.
"The offense has give me a lot of run support and the defense behind me has been great," Kelly said. "I'm just trying to keep the ball down in the zone and let them make the plays."
Kelly, acquired with Anthony Rizzo and Reymond Futures from the Red Sox for Adrian Gonzalez last December, has gotten his ERA below 4.00 for the first time in a month. The Florida native called himself "a better pitcher than I was in Spring Training."
Erik Hamren, Nick Vincent and Miles Mikolas combined for four innings of scoreless relief to close out San Antonio's eighth shutout. Mikolas struck out two in the ninth for his first save since a promotion from Class A Advanced Lake Elsinore.
Frisco's Richard Bleier (3-4) nearly kept pace with Kelly but gave up a run on seven hits over 6 1/3 innings. He struck out four and walked one.
The Missions scored the only run of the game in the fifth. Bryan Altman singled with one out, stole second and came home one out later on Daniel Robertson's base hit to left field.