PORTLAND — In a few weeks, it won’t be the heat as much as the humidity.

For the Portland Sea Dogs’ home-opener Thursday night, it wasn’t the cold (47 degrees and rapidly dropping at game-time) so much as the wind (20 MPH straight out) that made things interesting for anyone trying to grip or catch a baseball.

Luckily for the Sea Dogs, starting pitcher Keith Couch warmed up quickly and so did the bats for a 6-4 victory over the New Britain Rock Cats on a brisk, blustery night at Hadlock Field.

“What are you going to do? It’s the elements and you’ve just got to deal with it,” Couch said.

Couch, who allowed one unearned run in 5 2/3 innings in his first outing of the season April 4 at Reading, duplicated that line Thursday night. The run came in the first inning via an errant throw by third baseman Sean Coyle and Kennys Vargas’ sacrifice fly.

Couch allowed five hits struck out five, walked one and hit a batter.

“I threw my fastball early in the count,” Couch said. “Guys were swinging and they were aggressive, so I was able to pitch backwards. The fastball sets up the change-up. That’s a pitch that’s come a long way for me and it worked well.”

“He grinded through almost six innings,” said Billy McMillon, a former Sea Dogs player (1995) making his Hadlock managerial debut. “He pitched around an error in the first, gave up a run, but competed well.”

Carlose Rivero led the Sea Dogs offense going 3-for-4 with a double, two RBIs and two runs scored. Mookie Betts was 2-for-4 with a triple and two runs scored. New Britain out-hit Portland, 11-10.

Portland tied the game in the second on back-to-back one-out doubles by Rivero and Matt Spring. After an infield hit by Coyle moved Spring to third, Peter Hissey gave the Sea Dogs the lead with a ground out to short.

Coyle’s two-out single made it 3-1 in the fourth. Another two-out single, this one by Rivero, added two more runs to Portland’s lead in the fifth.

“It goes back to our early work,” McMillon said. “We work on trying to get a good pitch and it just so happened we got some big hits with runners on base with two outs.”

Betts, who was the Red Sox Minor League Player of the Year in 2013 according to Baseball America, showed off his speed when his fly ball to center got caught up in the wind and eluded centerfielder Corey Wimberly. Betts dove into third base as shortstop Aderling Mejia’s cutoff throw skipped past the bag and off the fence in front of the box seats. Betts popped up and hurried home for Portland’s sixth run to the delight of what remained of the announced crowd of 6,022.

“He gives us really good at-bats, a lot of energy,” said McMillon, who managed Betts at Single-A Salem last year. “He gives us a spark. I think that’s a part of his game. You don’t see that kind of intensity and attitude in a lot of guys, and it’s fun to watch.”

Michael Olmsted replaced Couch and pitched a scoreless inning-and-a-third. The Rock Cats scored one in the eighth and two in the ninth off Noe Ramirez to close the gap.

Ramirez put the tying runs on with two out before giving way to Jose Valdez, who got Daniel Ortiz to ground out to second to close it out.