Marcum had just one losing season while with Toronto and Milwaukee during his first seven years in the majors. He signed a one-year, $4 million contract with the Mets, then opened the 2013 campaign with nine consecutive setbacks.
He ended that drought by allowing just four hits over eight innings with two walks and two strikeouts. Marcum avoided becoming the first New York pitcher in 20 years to begin a season 0-10.
Marcum gave way to Bobby Parnell, who earned his 13th save with a 1-2-3 ninth.
The Mets scored all their runs in the fifth with two of them being unearned. A one-out fielding error by shortstop Alexei Ramirez on a grounder by Juan Lagares allowed both Josh Satin and Andrew Brown to score. Lagares came in later in the inning on an infield single by Eric Young.
The three runs and the loss were charged to John Danks (1-5), who worked 7 1/3 innings.