NEW BRITAIN, Conn. — Henry Owens of the Portland Sea Dogs experienced defeat for the first time in more than two months Thursday night.

Owens allowed a grand slam to Kennys Vargas in the third inning that propelled the New Britain Rock Cats to a 7-1 victory before 5,721 at New Britain Stadium.

“I put (a change-up) right down the middle of the plate, so definitely not where I wanted it,” said Owens, who described his performance as  poor. “He capitalized on a mistake.”

The setback snapped a franchise-record nine-game winning streak for Owens, who suffered his first loss since May 19.

Owens (13-4) was denied in an attempt to become the first Portland pitcher to win 14 games in a season.

He was outdueled by 20-year-old Jose Berrios in a matchup of starting pitchers in the Futures Game on July 15.

“I took it like any other start,” Owens said. “I’m not going to get over-amped or try to do too much. He pitched a good ballgame and I didn’t.”

Berrios (1-2), rated the No. 3 pitcher in the Minnesota Twins’  organization, earned his first Eastern League win in his third start for the Rock Cats.

He allowed one run and three hits over seven innings, with a walk and four strikeouts in his New Britain Stadium debut.

Berrios, the highest drafted pitcher to ever come out of Puerto Rico, taken by the Twins with the 32nd overall pick in 2012, pitched for Puerto Rico in the 2013 World Baseball Classic.

“Everybody was putting good swings on him,” said Blake Swihart, who had two of the Sea Dogs’ three hits. “Those balls get through, it’s a completely different ballgame. It just wasn’t our night.”

Owens, ranked as the Red Sox’s top pitching prospect by the Baseball America publication, logged a 1.62 ERA during his winning streak and his 13 victories were tops in the minor leagues.

But Owens was knocked out after four innings, matching his  shortest outing of the season.

Tagged for five runs and five hits, Owens walked four, one shy of a season high. The Rock Cats drove up his pitch count (87) with a patient approach.

Vargas, who was 3 for 3, blasted his 17th home run over the left-field fence to give New Britain a 4-0 lead.

Portland got its run on Michael Almanzar’s RBI groundout in the fourth, but the Rock Cats got it back on Aaron Hicks’ RBI single in the bottom of the inning, then added two runs against Portland’s bullpen.

Berrios retired the final 12 batters he faced after giving up a double to Swihart in the fourth, the last base runner for the Sea Dogs.

The Sea Dogs, who had a nine-game road winning streak in New Britain snapped, did hit some balls hard that didn’t fall in.

“It’s just one of those nights for us,” Swihart said.

While the Sea Dogs continue to enjoy a 4 1/2-game lead over Binghamton in the Eastern Division – Binghamton lost 6-5 at Trenton – they lost for the ninth time in their last 10 road games.