It took one defeat for the questions for the Mets to begin.

There were questions about Richard Lovelady — the last man to crack the Opening Day bullpen — pitching in a tie game in extra innings for a second straight day.

There were questions about Francisco Lindor being waved home in the bottom of the 10th, an aggressive green light from third base coach Tim Leiper that backfired.

Questions tend to arise after frustrating losses, and the Mets suffered their first in a 4-3, 10-inning setback to the Pirates on Sunday that meant their first series victory of the season was not a sweep.

There were other reasons that the 36,940 on hand for a gorgeous, if chilly, afternoon at Citi Field did not go home happy: Mets hitters struck out 16 times — including Lindor, Juan Soto and Bo Bichette opening their afternoon against Carmen Mlodzinski 0-for-6 with six strikeouts — and went 2-for-10 with runners in scoring position; Mets pitchers walked eight batters in 10 innings; Nolan McLean, who did settle down, could not find the strike zone in a lengthy, one-run first inning, seven of his first eight pitches balls.

Brad Penner-Imagn Images

But the game was lost in the 10th, when Lovelady — who had pitched Saturday, throwing 21 pitches while allowing the automatic runner to score but avoiding further damage — took the mound. Lovelady followed five mostly strong, two-run innings from McLean and four excellent, scoreless innings from Huascar Brazobán, Sean Manaea and Luke Weaver.

Notably unused were closer Devin Williams and Brooks Raley, both of whom had pitched Saturday and had thrown fewer pitches (19 and 11, respectively) than Lovelady.

Williams was unavailable, manager Carlos Mendoza later explained, because he “got hot” during Thursday’s Opening Day, when he warmed up but did not enter the game, then pitched a stressful inning Saturday. On the first weekend of the season, Mendoza did not want to turn to Williams for what he deemed roughly a third day out of four.

Mets shortstop Bo Bichette reacts after striking out during the third inning at Citi Field. Corey Sipkin for the NY POST

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Raley was not available on a back-to-back, Mendoza said, as the club eases the lefty into the season. The 37-year-old returned midseason last year from Tommy John surgery.

And so it was a not exactly fresh Lovelady who quickly let up a go-ahead RBI single to Ryan O’Hearn, issued two two-out walks and then was burned by another RBI single from Henry Davis that created a cushion for the Pirates.

That cushion was needed. In the bottom of the inning, Lindor drew a leadoff walk before Soto drilled an opposite-field double that one-hopped the wall in left-center.

As soon as the ball was hit, Lindor thought he could score. So did Mendoza. Apparently so did Leiper, who waved in automatic runner Francisco Alvarez and then kept the windmill turning for Lindor.

Center fielder Oneil Cruz chased down the ball and threw a one-hopper to shortstop Jared Triolo, who made a nice pick and threw a two-hopper to Davis. The catcher grabbed the ball and gloved Lindor in the face a second before Lindor could reach the plate.

Mets pitcher Nolan McLean (26) reacts after giving up a run during the first inning at Citi Field, Sunday, March 29, 2026, in Queens, NY. Corey Sipkin for the NY POST

The Mets — who could have had Lindor as the tying run at third and Soto as the winning run at second with no outs and Bichette and Jorge Polanco due up — instead settled for Soto at second with one out. After a groundout and a flyout, he was stranded and the game was lost.

The Mets were surprised Lindor was gunned down, not because they felt Leiper got too excited, but because the Pirates, who were sloppy all series, conducted the relay well.

“Coming into this series, this is a team that we targeted,” Mendoza said before the Mets began the first road trip of the season with St. Louis and San Francisco. “We were going to be aggressive, and they executed. You’ve got to give them credit.”

Lindor echoed the sentiment.

“I think I would’ve scored. I took a little bad of a route,” said Lindor, who was down for a few moments from the hard tag but said he was OK. “But I’m on board with Leip sending me there because we have talked about being aggressive.

“He made the right call.”