Pete Alonso's mammoth three-run homer fueled a five-run first inning Saturday night for the New York Mets, who hung on for an eventful 8-7 win over the visiting St. Louis Cardinals.

The Mets snapped a two-game losing streak but might have lost winning pitcher Noah Syndergaard, who exited with none out in the seventh due to a right hamstring strain.

The Cardinals lost for the second time in six games.

Alonso's homer off Michael Wacha (4-3) bounced off the facing along the third deck in left field at Citi Field.

J.D. Davis collected a career-high four hits, including a solo homer in the second, and finished a triple shy of the cycle for the Mets, who received RBIs in the first from Wilson Ramos (double) and Carlos Gomez (sacrifice fly). New York added pivotal insurance runs in the sixth via an RBI single by Michael Conforto and a bases-loaded walk drawn by Todd Frazier.

The Cardinals scored once apiece in the first (Dexter Fowler homer), third (Marcell Ozuna RBI single) and fifth (Fowler sacrifice fly) before scoring three times in the seventh and threatening in the eighth.

In the seventh, Syndergaard gave up a leadoff single to Yairo Munoz before leaving during an at-bat against Jose Martinez, who finished off his walk against Robert Gsellman. Matt Carpenter followed with an RBI double, after which Fowler delivered a run-scoring single and Paul DeJong lofted a sacrifice fly. Ozuna then lined into an inning-ending double play.

Syndergaard (5-4) allowed five runs (four earned) on six hits and two walks while striking out five.

The Cardinals loaded the bases in the eighth against Seth Lugo, who escaped the jam by striking out Carpenter. Edwin Diaz barely earned his 15th save in the ninth, when he gave up a two-out RBI single to Yadier Molina. Kolten Wong followed with a bloop double to right, but Mets second baseman Jeff McNeil whirled and threw home to get pitcher Jack Flaherty, who was pinch-running for Molina, for the final out.

Wong had two of six stolen bases by the Cardinals.

Wacha allowed six runs (five earned) on seven hits and one walk while striking out four in four innings.

Home plate umpire Brian O'Nora left in the third inning, when he ran off the field in obvious discomfort shortly after taking a foul ball off his groin. O'Nora was replaced by first base umpire Chad Whitson.

--Field Level Media