Walters allowed one hit over 5 2/3 shutout innings as the Great Falls Voyagers beat the Missoula Osprey, 8-3, in Game 1 of the best-of-3 Pioneer League semifinals.
"My changeup on the outside part of the plate was working against the righties," said Walters, who was named Pioneer League Pitcher of the Year after going 9-0 with a 4.03 ERA during the regular season. "I was also able to locate my fastball. I was using my slider against the lefties."
"I was a little more nervous than usual, but I was still confident in myself. I had faced these guys before and had success."
Walters, selected by the White Sox in the 11th round of this year's Draft, fanned seven and walked four. He struck out the side around a walk in the fifth, then retired the first two batters in the sixth before turning things over to the bullpen.
Austin Evans surrendered three runs on two hits and a walk in one inning, but Jon Gulbransen and Blake Drake combined on 2 1/3 scoreless frames. Drake recorded the save.
Qualon Millender went 3-for-3 with a walk, an RBI and a run scored for Great Falls.
Tyler Linton slugged a three-run homer for Missoula, which hosts Game 2 on Saturday.
In other Pioneer League playoff action:
Raptors 3, Owlz 2
Noel Cuevas' two-run single in the seventh inning erased a 2-1 deficit as Ogden rallied to take the opener in Orem. Three relievers combined to allow one hit over 3 2/3 scoreless innings for the Raptors. Box score