BOSTON — Alex Rodriguez and David Ortiz made a pair of young fans very happy at Fenway Park on Friday night.

Ortiz, who hit what proved to be the game-winning home run against the Yankees, earlier in the day had promised to hit a home run for a sick child in a video message posted on former Red Sox first baseman Kevin Millar’s Twitter account.

Then he did.

That promise came hours before Rodriguez told a young fan who recently lost his father that he would give him his bat if he hit a home run.

Then he did.

A-Rod hit a long shot off a light tower over the Green Monster in the second inning of the Yankees’ 4-2 loss to the Red Sox.

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As he crossed home plate, Rodriguez motioned to the bat boy to give the home run bat to 8-year-old Red Sox fan David Moss, who was seated next to the Yankees’ dugout and chatted with A-Rod while he was in the on-deck circle.

Rodriguez said on Saturday that he was unaware that Moss had lost his father, Andy, to cancer last September and was simply fulfilling a promise to the young fan, who originally asked him for a souvenir. Rodriguez told him he would be happy to hand over his bat if he hit a home run.

Moss and his mother and sister traveled to Boston from Mesa, Arizona, to attend the game on his eighth birthday. Before the exchange with A-Rod, the family met Ortiz.

Ortiz had a busy pregame. He and Millar appeared in a video message for 5-year-old Maverick Schutte, a Red Sox fan from Wyoming who was born with a congenital heart defect, according to ESPN.com.

“You take care, buddy, and I’m going to hit a home run for you tonight. Remember that,” said Ortiz, who is in his final season.

Yankees videos

After Ortiz’s two-run homer off Dellin Betances in the eighth inning led the Red Sox to victory, Millar posted a video from Schutte thanking Ortiz.

“Millar was crying when he was showing me the video that Maverick sent him back,” Ortiz said, according to ESPN.com. “It was very touching. And I start thinking about it right after, when I got home. That was when I really was like, ‘Wow, I can’t believe this really happened.’ And Millar told me that his parents haven’t seen him that happy in a long time. He has been very sick. I always say there’s something special out there. I’m a huge believer in that.”