NEW BRITAIN, Conn. — Jose Berrios (1-2) earned his first Double-A win and Kennys Vargas hit a grand slam as the New Britain Rock Cats (51-52) beat the Portland Sea Dogs (66-39), 7-1 on Thursday night in the series opener at New Britain Stadium.

Berrios was sensational in his home debut, tossing seven strong innings on three hits, no walks and four strikeouts. The right-hander beat Henry Owens (13-4), who had his nine-game winning streak snapped.

Cole Johnson and Berrios closed out the victory by retiring the final 18 batters faced.

Owens almost escaped a bases-loaded jam in the third inning, but with two outs, Vargas cleared the left-field wall on a 1-2 pitch for a grand slam, giving the Cats a 4-0 lead. Vargas finished 3-for-3 with two walks. Owens faced eight batters in the inning, yielding three hits and two walks. On the night, the lefty lasted just four innings, suffering his first loss since May 19 against Binghamton.

Portland scored its lone run against Berrios in the fourth. Blake Swihart led off with a double, advanced to third on a wild pitch, and scored on a groundout by Michael Almanzar. Berrios retired the final 12 batters faced, and induced two double plays in the first two innings.

New Britain added a run in the fourth in Owens’ final frame. With two outs, Aaron Hicks nailed a run-scoring single. Owens yielded five runs, five hits, four walks and fanned six over four innings. The runs were the most allowed since April 27 against Trenton.

Jeremy Kehrt worked three innings for Portland, giving up two runs on sacrifice flies by Hicks and Brad Boyer.

The Sea Dogs and Rock Cats continue their four-game weekend series with game two tonight at 7:05 p.m. at New Britain Stadium. Portland is slated to send Brian Johnson (8-3, 2.32) to the hill against New Britain’s Jason Wheeler.