With 19 family members and friends on hand, the right-hander gave up just a two-run homer to Wilmer Flores in 4 1/3 innings in a no-decision.
"There's nothing like getting thrown in the fire," Esch said.
Rated by MLBPipeline.com as the Marlins' 10th best prospect, Esch had a whirlwind 24 hours. It started on Tuesday night, when he was with Triple-A New Orleans at Colorado Springs. He was informed Phelps may not be able to pitch, and plans were made to get him to New York.
From St. Paul, Minn., Esch attended Cretin High, the same school that produced Paul Molitor and Joe Mauer. He went on to Georgia Tech, where he was a teammate of Marlins infielder Derek Dietrich.
On Wednesday, Esch had his parents, some cousins and friends come in to New York from Minnesota, Philadelphia and Baltimore.
"Jacob flies in today, and gives us a good outing," Marlins manager Don Mattingly said. "Hangs a breaking ball to Flores. Other than that, he was pretty good."
Esch impressed in the first inning, retiring the Mets in order, striking out Asdrubal Cabrera and Yoenis Cespedes. But he walked Curtis Granderson to lead off the second, and Flores took him deep to left, putting New York ahead, 2-1.
"I wish I could take back one mistake," Esch said. "It would've taken the pressure off everybody else later in the game. You know what? Those things happen."
Esch's biggest moment came in the fourth inning when he got out of a bases-loaded, no-out jam. With Miami trailing by a run, Esch induced a double-play grounder from Bartolo Colon and then retired Jose Reyes on a grounder to second.
"Bases loaded, nobody out, big league debut," Esch said. "Bartolo Colon is at the plate. Throw him a ball that he's going to hit a ball on the ground, get us a double play."
Like clockwork, it happened.
Actually, Esch's body clock was going full speed since he found out he was starting Tuesday, and his plane arrived in New York around 2 p.m. ET with his start roughly five hours later.
"The couple of hours on the plane were probably the biggest two hours of sleep I've had in my life," he said.
Although the Marlins have now dropped five straight to finish 10-18 in August, the team is still in striking distance in the National League Wild Card race with a little more than a month remaining.
"Yesterday was a more emotional day for me," Esch said. "Today I was excited to get up here and join a pennant race."