The Red Sox lost their first three games this spring, and they seem to have recovered nicely.

Their Double-A affiliate showed similar resiliency Thursday.

The Portland Sea Dogs bounced back from a lopsided season-opening loss Tuesday and an inauspicious start Thursday to sweep the visiting New Hampshire Fisher Cats in a seven-inning doubleheader before a crowd of 1,240 at Hadlock Field.

A home run by Johan Mieses that cleared the 37-foot wall in left field broke a sixth-inning tie to give the Sea Dogs a 4-3 victory in the nightcap. Earlier, the Dogs overcame a five-run deficit to beat the Fisher Cats 9-6.

Both Sea Dogs starting pitchers were making their Red Sox organizational debuts, having arrived via trade over the winter.

In the opener, control problems plagued Frank German, who came over from the Yankees as part of a deal that included Red Sox reliever Adam Ottavino. German didn’t make it out of the first inning. He walked three and gave up two extra-base hits, and his errant throw to first on a comebacker opened the door to four unearned runs.

Josh Winckowski fared better in the nightcap. Originally a Blue Jay, Winckowski was traded twice in a span of 15 days, first to the Mets and then to the Red Sox in a deal involving Andrew Benintendi and Kansas City.

Winckowski breezed through a perfect first inning on seven pitches. He walked three in the second, one with the bases full, and pitched into the fourth without allowing a ball hit to the outfield grass in the air. He induced eight ground balls, only one of which resulted in a hit. He struck out four and walked four, throwing 46 of his 70 pitches for strikes.

Jack Lopez doubled twice in the nightcap. He and Tanner Nishioka, both seeing their first action of the season, delivered two-out hits to spark the first-game comeback. Lopez drove in two runs with a single in the fifth to put the Sea Dogs ahead 6-5. After a walk, Nishioka bounced a ball up the middle to score two more.

The Sea Dogs had trimmed New Hampshire’s lead to 5-3 with help from a two-out, two-run double by Ryan Fitzgerald. Portland outhit New Hampshire 9-4, and Sea Dogs relievers Dominic LoBrutto, Enmanuel DeJesus (1-0) and Jose Adames held the Fisher Cats in check after German departed.

Pedro Castellanos and Joey Meneses each had two hits for the Sea Dogs, who sent 12 batters to the plate in a six-run fifth. In the sixth, both benches emptied after Portland’s Ronaldo Hernandez took several steps toward New Hampshire reliever Connor Law following a Law fastball came too close for the batter’s liking.

Pitchers scurried in from both bullpens to join the crowd, kept peaceful by managers Corey Wimberly of Portland and Cesar Martin of New Hampshire as well as by the umpiring crew. Warnings were issued to both teams, who are scheduled to meet three more times this weekend.

Slugging first baseman Triston Casas, rated the top prospect in the Red Sox minor league system, lined a single to right for his only hit of the night, but showed smarts on the basepaths (advancing to second after tagging up on a sacrifice fly when the throw home was off target) and at the plate (choking up with two strikes to slap a ball knocked down by Fisher Cats third baseman Samad Taylor, whose hurried throw was in the dirt and allowed Casas to reach base and eventually score the tying run).

Casas struck out swinging in all three plate appearances in the nightcap to finish the day 1 for 7.

Outfielder Jeisson Rosario, another top Red Sox prospect, went 0 for 3 with a walk in Game 1. He lined out sharply to center, struck out twice and sat out Game 2.

NOTES: Tickets for June Sea Dogs games will go on sale Wednesday, either through the team website (seadogs.com) or by calling the ticket office at 879-9500.

Prices range from $19 for box seats to $18 for reserved and $17 for grandstand. Fans must buy the entire pod of seats, which range up to eight.

This story has been updated at 8:45 on May 7 to correct the name of Portland’s starting pitcher.