Mark Vientos hits walk-off home run in extras as Mets avoid sweep

Mark Vientos didn’t make the Mets out of spring training.

He’s only on the MLB roster now because Starling Marte went on the bereavement list Saturday, needing to tend to a family issue. The 24-year-old didn’t even start Sunday, entering in the bottom of the ninth as a pinch-hitter.

But Vientos emerged as the unlikely hero Sunday, slugging a walk-off home run in the Mets’ 4-2 victory in 11 innings over the Cardinals.

The improbable victory staved off a three-game sweep and gave the Mets a win in a game they began 0-for-15 with runners in scoring position.

Vientos’ home run off of Matthew Liberatore followed Harrison Bader’s game-tying single on an 0-2 pitch.

Mets starter Jose Quintana limited St. Louis to one run and three hits over eight excellent innings. The Cardinals went 0-for-8 with runners in scoring position against the left-hander, scoring their only run against him on Michael Siani’s fifth-inning RBI safety squeeze.

The 36-year-old Quintana, who started Opening Day in place of injured ace Kodai Senga, and now boasts a 3.48 ERA this season.

The Mets had lost five of six games before Sunday’s win, which put them back above .500 at 14-13.

They continue their seven-game home stand on Monday night, when they’re scheduled to open a four-game series against the Cubs.