DeGrom, the reigning National League Rookie of the Year, surrendered a two-run homer to Ryan Zimmerman in the first inning, then tossed five scoreless innings in a hard-luck loss.
The Washington Nationals beat the Mets 2-1 on Wednesday to even the season-opening series.
DeGrom departed after six innings, having allowed two runs on six hits and two walks (one intentional). He struck out six.
DeGrom threw 92 pitches, 64 of them for strikes. The Mets have resolved to keep his pitch count on the conservative side early in the season.
DeGrom had allowed only seven homers in 140 1/3 innings last season.
Tough call: A half-inning after Zimmerman’s two-run homer, the Mets pulled within 2-1 on Travis d’Arnaud's RBI single in the second.
With the bases loaded and two outs later in that frame, the Mets ended up on the wrong side of a disputed call. Plate umpire Mike Everitt called out Curtis Granderson looking on a full-count offering from Jordan Zimmermann at the top of the strike zone as the Mets stranded three baserunners.
Granderson had started trotting to first base when Everitt called the third strike.
Granderson’s strikeout began a streak of 11 straight retired by Zimmermann. Lucas Duda finally had a one-out single into the right-field corner in the sixth.
Odds & ends: The start of the game was delayed 56 minutes because of rain. … Wilmer Flores grounded out to end the top of the seventh against Craig Stammen, stranding Kirk Nieuwenhuis at second base. … Working in relief in his season debut, Rafael Montero allowed a one-out double to Michael Taylor in the seventh. Montero escaped the inning unscathed, then tossed a scoreless eighth as well. … The Mets have scored one earned run through two games.
What’s next: Matt Harvey Day! Harvey makes his first regular-season start in 593 days. He opposes Stephen Strasburg in Thursday 1:05 p.m. ET rubber game. It marks a rematch of a riveting early season faceoff from two years ago between Harvey and Strasburg.