The Mets prospect allowed one hit and recorded a career-high 10 strikeouts over 6 2/3 innings as Rookie-level Kingsport blanked the Bristol White Sox to complete a doubleheader sweep.
Mitchell (4-1) did not allow a hit until Michael Johnson singled with one out in the sixth. He walked three, including Collin Kuhn with one out in the seventh, then fanned Michael Schwartz before reaching his limit of 90 pitches.
"Everything was really working," said Mitchell, who throws a fastball, changeup, slider and curveball. "I was pounding the zone with my off-speed pitches. I mixed them in there all the time. I think they are all pretty solid."
It was the second time this season that Mitchell (4-1) pitched at least five hitless innings against Bristol. He walked one on June 25 in a 10-3 win and was named Appalachian League Pitcher of the Week. This time, Mitchell hoped he'd be able to finish off his first no-hitter.
"I was going for it, I tried," he said. "We had a lead, so in the back of my mind I wanted to get us back in the dugout. So I was throwing in the zone and hoped they hit it."
Selected in the 12th round of the 2010 Draft, Mitchell has excelled in his return to Kingsport, posting a 3.41 ERA and 35 strikeouts over 31 2/3 innings. He's limited opponents to a .186 average to rank third in the league and is second with a 0.98 WHIP.
"It's not my choice, I'm happy where I'm at," he said of a potential promotion. "If they want to move me up, that's fine, but we've got a good team here. I just want to keep going good and give my team a chance to win."
Greg Pron homered, doubled and drove in three runs, while Tant Shepherd scored twice for the Mets, who have won seven straight after losing seven of eight.
Kingsport took the opener, 2-0, as Brian Valenzuela gave up two hits over five innings.