The trades of Max Scherzer and Justin Verlander reopened a spot in the Mets’ rotation this month for Tylor Megill, and the righty posted his finest start since early this season Monday night against Scherzer’s new playoff-contending team.

Megill tossed six innings of one-run ball — but Trevor Gott couldn’t hold a 3-2 lead in the ninth — as the Mets’ bullpen let them down again in a 4-3 loss to the Rangers, at Citi Field.

Gott nearly escaped with two runners in scoring position in the ninth with strikeouts of Leody Taveras and Marcus Semien.

Following an intentional walk to Corey Seager, however, Nathaniel Lowe ripped a two-run single to right to put Texas ahead for the first time.

Scherzer, who won’t pitch in this series in his first trip back to Flushing following his trade-deadline move to Texas, received more boos than cheers when the Mets (60-72) welcomed him back with a video tribute minutes before the first pitch.

Megill provided a rare bright spot in his season, allowing five hits and striking out a season-high eight before turning over a 3-1 lead to the bullpen to start the seventh.

He had thrown six scoreless innings against the Marlins on April 7, in his second start this year.

The 28-year-old Megill had spent more than six weeks at Triple-A Syracuse this summer after an otherwise ragged first half, but he was summoned back to the Mets following the white-flag trades of co-aces Scherzer and Verlander in late July.

Megill hadn’t been much better over his first four outings since rejoining the rotation, posting a 6.86 ERA over 19 ²/₃ innings, including five earned runs apiece in starts against the Orioles and the Braves.

But Megill had it all working against the team with the highest OPS (.795) and most runs scored (727) in the American League through Sunday.

He allowed only two singles and struck out seven over his first five scoreless frames.

Brandon Nimmo had staked Megill to a 2-0 lead in the third with a two-run shot to right off Rangers starter Jon Gray, extending his career-high total to 19.

DJ Stewart also went deep with a solo blast to right in the fifth, his sixth in his last 12 games.

The Rangers (74-57) got to Megill (96 pitches) for a run in the sixth on doubles by Semien and Adolis Garcia, and he was replaced by reliever Sean Reid-Foley the following inning.

They added a second run — charged to Brooks Raley — in the eighth before grabbing the lead with two runs in the ninth.