Matt Harvey is still without a nickname, but “One and Done” might be appropriate for the Mets ace.

That is, if Harvey dares surrender one run, his chances of winning the game are about done. So yesterday was just another day at the office for the stud right-hander, as he suffered his first loss of the season in the Mets’ 2-1 defeat to the Cardinals at Citi Field.

Harvey (5-1) allowed one run over seven innings, ending his unbeaten streak at 14 starts dating to last season. In three of his last four starts, Harvey has allowed only one run. But over that stretch doesn’t have a win.

“The wins and losses don’t mean anything to me, personally, it’s a matter of the team winning,” Harvey said.

Even so, manager Terry Collins felt compelled to speak with him after the game, just to remind Harvey that a personal winless drought dating to May 17 at Wrigley Field hasn’t been the pitcher’s fault.

“Probably four more runs [total] and he is 8-0 or 9-0 coming into today,” Collins said. “That just tells you how well he has pitched and he pitched another great game today and just has got to keep doing it. There’s nothing else to say except, ‘Keep going out there and getting outs,’ as I just told him.”

Adam Wainwright (10-3) dominated the Mets, limiting them to four hits and two walks over seven shutout innings. The only semblance of a rally against the right-hander came in the fourth inning, when the Mets put two runners aboard only to watch the threat fizzle on Lucas Duda’s long fly out.

The Mets (24-37) got a run in the ninth on Marlon Byrd’s homer against Edward Mujica. The tying run was left stranded at third base when pinch-hitter Josh Satin struck out against Mujica.

Harvey allowed five hits and one walk with seven strikeouts. Scott Rice was charged for a run in the eighth on Allan Craig’s RBI single against LaTroy Hawkins.