A starting pitcher is expected to set the tone for a baseball team, and over his previous five games, Sea Dogs right-hander Denyi Reyes had been decidedly sour with his opening inning.

On Wednesday night, under balmy skies amid the promise of fireworks, the tone set by Reyes was as sweet as the strawberries finally ripening in nearby fields.

Reyes worked out of an early jam to throw a scoreless first inning for the first time since May and the Sea Dogs responded with a 9-2 victory over the Trenton Thunder before a sellout crowd of 7,368 at Hadlock Field.

The victory extended Portland’s winning streak to four, matching a season high, and wrapped up a four-game series sweep. The Sea Dogs, who were coming off an 0-4 trip to Reading, hadn’t swept such a series at Hadlock since July of 2015 against New Hampshire.

“To be able to respond with four wins here, especially against Trenton, a team we’re chasing, is a big boost for us,” said Sea Dogs Manager Joe Oliver.

Third baseman Bobby Dalbec homered for the fourth time in five games, a two-run blast to right-center that traveled an estimated 404 feet and raised his league-leading total to 18. He finished with two hits and scored three runs, the first on a balk in the first inning after Luke Tendler’s RBI double.

“That’s where my strength is,” said Dalbec, the top-ranked prospect in the Red Sox farm system. “I never really knew how to pull the ball, but the past couple years I’ve kind of learned. This is me being easy. If I’m trying to do too much, I won’t hit any opposite-field home runs.”

The Sea Dogs broke open a 4-2 game with a five-run fifth that included a double by C.J. Chatham and a two-run triple by Jeremy Rivera. Trenton helped out with a pair of errors and Brett Netzer added a blooped RBI single to the opposite field.

Chatham, the Portland shortstop who left the first game of Tuesday night’s doubleheader after fouling a pitch off his knee and later tweaking it on a catch in shallow left field, showed no ill effects on Wednesday. He showed agility in the field and on the basepaths and collected two hits for a fourth straight game, raising his team-leading batting average to .325.

Instead of a scheduled day off, Chatham asked to play Wednesday night.

“I’m glad I did,” he said.

The Sea Dogs are 4-11 in games started by Reyes (3-9), who retired the first two men before allowing a single and hitting a batter. Instead of yielding a first-inning run, as has been the case in each of his previous five starts, Reyes induced a fly to left to strand the runners.

His next two innings were perfect and, except for a two-run homer by Mandy Alvarez in the fourth, Reyes kept the Thunder off balance and off the scoreboard. He held Trenton to six hits in seven innings, didn’t walk a batter and struck out one.

“He hangs in there and gives you a chance to win every time,” Abbott said. “Take away maybe the first three weeks, and he’s pitched really well. He changes speeds, moves the ball around and makes them scratch their heads as they’re going back to the dugout.”

Wednesday’s game marked the eighth straight start Reyes has lasted at least six innings. Relievers Durbin Feltman and Matthew Gorst each followed with a scoreless inning.

The Sea Dogs head to New Hampshire Thursday for a four-game series against the Fisher Cats in advance of the All-Star break.