DJ Stewart hit a tiebreaking three-run homer in the sixth inning Tuesday night, lifting the New York Mets to a 4-2 win over the Chicago Cubs.

Stewart had just three hits in his previous 23 at-bats before sending a no-doubt drive into the second deck in right field against Adbert Alzolay (1-3) to give New York a 4-1 lead.

With the arrival of designated hitter J.D. Martinez last week and the return Tuesday of right fielder Starling Marte from the bereavement list, Stewart's roster spot could have been in jeopardy. But the Mets hung onto the left-handed batter, and he certainly delivered against the Cubs.

All three runs against Alzolay were unearned due to a throwing error by Gold Glove shortstop Dansby Swanson. First baseman Patrick Wisdom also made a throwing error in the first, leading to Pete Alonso’s sacrifice fly.

Sean Reid-Foley (1-0) tossed a hitless sixth. Jorge López earned his second save after giving up a run in the ninth, when Mike Tauchman doubled and scored on a groundout by pinch-hitter Matt Mervis.

Miguel Amaya had a sacrifice fly for the Cubs in the second.

Chicago starter Javier Assad and Mets counterpart Sean Manaea each allowed one run in five innings. The teams were hitless in six plate appearances with runners in scoring position against the starters.

Cubs LHP Shota Imanaga (4-0, 0.98 ERA) looks to continue the historic start to his career Wednesday night, when he opposes Mets RHP José Buttó (0-1, 2.86) in the third game of the four-game series. Imanaga is the first pitcher since 1901 to open his career 4-0 with a sub-1.00 ERA and at least 28 strikeouts in his first five starts.