There’s a Met whose season debut exceeded the lofty expectations. Problem is, he’s stashed in Las Vegas.

Hours after the Mets put the finishing, fumbling touches on a season-opening sweep at the hands of the Nationals on Thursday in Flushing, Triple-A pitching prospect Rafael Montero put together quite a nice little start on minor league Opening Day.

Montero required just 79 pitches to get through six scoreless innings against visiting Fresno. He struck out five, allowing four hits and no walks.

“He really didn’t [make mistakes],” 51s interim pitching coordinator Tom Signore said. “I’m looking at the spray chart right now and those [hits] were pitches that were down and hit on the ground. We’ll take our chances with balls hit on the ground, especially here in the thin air.”

The 23-year-old Montero is coming off an impressive spring training that positioned him for a midseason callup — either to fill in as a starter or to bolster a Mets bullpen that has pitched to a 10.61 ERA through three games.