PORT ST. LUCIE — Johan Santana called it a memory he will never forget, and few Mets fans will disagree. 

The Mets announced Monday they will celebrate the 10-year anniversary of Santana’s no-hitter during a pregame ceremony at Citi Field on May 31 against the Nationals. 

On June 1, 2012, a Santana changeup — of course it was a changeup — struck out St. Louis’ David Freese for the first no-hitter in franchise history after 8,019 regular-season games. 

Josh Thole, Santana’s catcher that night, also will be honored, and both will participate in Old-Timers’ Day. 

“I can’t believe it’s been 10 years almost since we made history,” said Santana, who gutted through 134 pitches but knew what it meant to the organization. 

He needed help from several sources, from Thole to an umpire ruling Carlos Beltran’s laced would-be hit down the third-base line was foul — Santana said he has never talked with Beltran about it — to Mike Baxter’s seventh-inning running catch that smacked him against the left-field wall to trust from then-manager Terry Collins. 

After the eighth inning, “He asked me how I felt, and I said I felt good and I was not coming out,” Santana reminisced, having thrown 122 pitches up to that point. “And he told me I was his hero.” 

Santana posted an 8.27 ERA in 10 games the rest of the season before he was shut down and injuries set in that prematurely ended his major league career. 

“One hundred twenty, 125, 135 pitches — it didn’t matter,” said Santana, who is now a middle-school coach in Florida. “It was just the opportunity that I had then to do something that I had never done. … You take that chance.”