Yankee great Mariano Rivera opened up to The Post on Tuesday about the shooting of David Ortiz, saying, “It’s hard to see that happen to a guy like him.”

“He has a great heart, a giving heart,” Rivera said of Ortiz, with whom he had some memorable showdowns during the Yankees-Red Sox rivalry.

Calling himself “a friend but also a peer’’ of “Big Papi,’’ Rivera added, “It was so unfortunate.

“But thank God that he’s alive, and we are praying for his recovery and that he will be OK,’’ said Rivera, who in January was voted unanimously into the Baseball Hall of Fame. “Right now, we have to make sure he’s all right and to move on.”

Another Hall of Fame pitcher, Pedro Martinez, broke down in tears as he paid tribute to his former Red Sox teammate and fellow Dominican.

“I don’t have enough words to describe who David is, what David means to baseball,” Martinez told the MLB Network. “But I’m so disappointed to know that someone like David, who saved so many lives, can have someone after his life . . . It hurts me.”

Ortiz, 43, was shot in what cops believe was an orchestrated hit at a bar in the Dominican Republic on Sunday night. Police have yet to release a motive.

The Sox flew him from the isle to a hospital in Boston on Monday for treatment.