Daniel Murphy’s return to Citi Field Tuesday night as a member of the NL East rival Nationals for the first time since he inspired the Mets’ run to the National League pennant last season had all the trappings of a graduation ceremony.

Murphy accepted his NL championship ring from general manager Sandy Alderson, delivered a valedictory news conference, enjoyed a video tribute and accepted two standing ovations from Mets fans after the video and before his first at-bat leading off the second inning. The .400 hitter then fouled out, giving Mets fans another reason to cheer, and they left happy when the Mets scored a 2-0 win on solo home runs Curtis Granderson to start the game and by Michael Conforto in the third inning.

Coming off last season’s emotional thrill ride to the World Series, these rituals were necessary for Murphy and for Mets fans to cut ties forged over his 10 years in the organization, including the past seven in New York. It worked because he was booed before his second at-bat, a two-out bloop single.

Describing the crowd reception, Murphy said, “It was really nice of the organization to play that video, and the ovation from the crowd left me humbled to say the least.”

Asked if he smiled to himself when he was booed the second time around, Murphy addressed the new normal. “They’re not going to cheer me the next 20 times,” he said. “They’re wearing orange and blue, and I’m wearing red. You could feel the intensity. When Granderson hit the home run, you could feel it.”

Before the game, Alderson presented the MVP of the NLCS his ring. “I made it clear to him that, without his substantial contribution, none of us would be wearing that ring today,” Alderson said.

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True, but Alderson’s refusal to engage in meaningful free-agent negotiations made it clear the organization could live without him. So Murphy accepted the Nationals offer of $37.5 million over three years. The finality of the situation hit Murphy when the Nationals faced the Mets in spring training.

“I saw the orange and blue on the other side and I was wearing the red, it kind of put aside what had happened in New York,” Murphy said. “That’s not going to wash off easy . . . But the red gets more comfortable every day.”

Murphy carried his postseason success south to D.C., and is averaging .399 with five home runs and 23 RBIs, a 1.053 OPS and 19 multihit games.

“As far as the postseason last year, I just felt like the game was moving slower . . . and I was able to execute all the plans I was trying to against pitchers. That’s kind of where I’m at right now.”

Murphy thanked the Mets for the “classy” video tribute, but he added, “Once that ends and 7:10 starts, it’s prison rules out there, a division opponent.”

Mets videos

The only thing missing from Murphy’s rite of passage was his familiar walk-up music by the Dropkick Murphys, which would have been supremely appropriate because the Mets and their fans now count him among the departed.