The Blue Jays prospect allowed one hit over six innings and Alan Farina tossed a perfect seventh to complete the gem as the Fisher Cats blanked the New Britain Rock Cats, 4-0, to earn a split of Sunday's doubleheader.
In winning his last three starts, Carreno has allowed one run on four hits over 19 1/3 frames. He's fanned 22, walked 13 and hit three batters while holding opponents to a .069 average. The 24-year-old right-hander is third in the Double-A Eastern League with 53 strikeouts in 48 innings.
Carreno worked in and out of trouble throughout. He walked two in the first before fanning Chris Parmelee and Evan Bigley, plunked Mark Dolenc in the second and walked two more in the third before settling down for a perfect fourth.
After Chris Cates drew a one-out walk in the fifth, Chris Herrmann picked up the Rock Cats' only hit with a line drive to center with two outs. Carreno hit Joe Benson to load the bases but got Parmelee to ground out.
Carreno (3-3) worked a perfect sixth and finished with five walks and two hit batters.
Farina lowered his ERA to 1.76 with a 1-2-3 seventh.
John Tolisano got the Fisher Cats on the board in the third with a solo homer, his second of the season and second in three games. After Mike McDade singled home Darin Mastroianni in the sixth, Yan Gomes delivered a two-run blast in the seventh.
New Hampshire has won five of its last six games and improved to a league-best 13-6 on the road. It has a two-game lead over second-place New Britain in the Eastern Division.
Steve Hirschfeld (3-1) suffered his first loss of the season for the Rock Cats after yielding two runs on three hits over six frames. The right-hander, who fanned six and walked a pair, owns a 2.08 ERA and has held foes to a .175 average over 47 2/3 innings.
New Britain won the opener, 6-5.