The Brooklyn native allowed one hit and struck out eight over six dazzling innings as Class A Advanced Tampa one-hit Dunedin, 3-0, in the first game of Tuesday's doubleheader.
Betances (2-0) walked one and lowered his ERA to 0.50 in his third start for the Yankees coming off elbow ligament replacement surgery last year. Right-hander Jonathan Ortiz fanned one in the seventh to pick up his 13th save and finish off the one-hitter.
The right-handed Betances was the Yankees' eighth-round pick in the 2006 Draft and has steadily progressed through the organization's system despite arm pain. The 6-foot-8, 245-pounder was limited to just 44 1/3 innings in '09 before undergoing the arm procedure, but he's allowed just one earned run in 18 innings this season.
Betances allowed just two baserunners, walking Tyler Pastornicky to begin the game before surrendering a one-out single to John Tolisano in the fifth. He faced 19 batters, inducing five grounders and four fly balls, struck out the side in the first and fanned two in second, fifth and sixth innings.
The Grand Street Campus High School (Brooklyn, N.Y.) product allowed two runs over six scoreless innings in his previous start against Dunedin on June 15 after holding Lakeland to a run over six frames in his debut June 10.
The 22-year-old has 21 strikeouts in 18 frames after finishing a shortened '09 campaign with a 2-5 record and a 5.48 ERA in 11 starts for Tampa. He was a combined 9-5 with a 3.92 ERA in '08.
Ortiz, 20, has not allowed a run in nine of his last 10 appearances for Tampa. Signed by the Yankees in 2004, the Dominican right-hander was an All-Star in 2008 and '09.
Jose Pirela smacked a two-run double in the seventh.