Fans at the Cardinals-Mets game cheered when a man neatly caught a foul ball at Citi Field — until they realized it was Chris Christie.

The New Jersey governor then got loudly booed Tuesday night.

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The ovation quickly turned sour after Christie stood up and slapped hands with another fan. No matter that Christie gave the souvenir to a kid.

Christie was sitting in the third row, near the Mets dugout. In the third inning, St. Louis rookie Paul DeJong lifted a high foul that bounced in the stands, and Christie reached out with his left hand and snagged it.

The embattled Republican recently tried out for a spot on WFAN.