Betances allowed one hit and struck out a season-high 11 over six innings and Phillip Bartleski followed with three perfect innings as Class A Advanced Tampa blanked Fort Myers, 7-0, on Monday.
Betances (6-1), the Yankees' eighth-round pick in 2006, allowed a one-out single to Nick Romero in the second inning. He retired 11 in a row after that before ending his night by striking out his last five batters.
"I was getting ahead in the count," Betances said. "I felt like my arm speed was working well today. My curve was working well, I got a lot of strikeouts with that."
The New York native has made a complete turnaround from where he was a year ago, despite not leaving Tampa. Betances was 2-5 with a 5.48 ERA in 11 starts for the Yankees in 2009. This season, however, he is 6-1 with a 1.26 ERA in 11 starts and would lead the Florida State League in ERA if he qualified.
Betances, who did not pitch after June 24 last year because of an elbow injury, said renewed health is only partially responsible for his resurgence.
"I don't want to say I didn't pitch well because my arm didn't feel right, and now I feel 100 percent," he said. "Right now, I am just trying to go out every day and improve and be consistent with my mechanics. Last year my delivery wasn't fine. I am happy to go out there every five days and give the team a chance to win."
Bartleski, signed as a non-drafted free agent in 2007, struck out two in earning his third save. Betances raved about the 27-year-old's performance.
"Just to have the confidence in the bullpen, to know that they are going to go the distance and finish the job with three perfect innings, you can't ask more than that," Betances said.
Melky Mesa got the Yankees (23-12) on the board with a three-run blast in the fifth, his 15th of the season. Leadoff hitter Ray Kruml was 3-for-5, falling a homer shy of the cycle, and drove in two runs. Mitch Abeita reached base twice and scored a pair of runs.
Kane Holbrooks (1-2) took the loss for the Miracle, allowing four runs on 10 hits and striking out six over 5 2/3 frames. Former first-round pick Shooter Hunt struck out one in a hitless inning of relief.