By ABBEY MASTRACCO

New York Daily News (TNS)

After looking unbeatable a month ago, the Mets couldn’t beat the second-worst team in the National League.

To be fair, the series had already been won and the conditions were less than ideal. The Mets battled rain, wind and some questionable umpiring Wednesday night at Citi Field, in a 4-0 loss to the Pittsburgh Pirates, only the second shutout loss of the season and the first in more than a month (April 9 vs. the Miami Marlins).

Clay Holmes gave the bullpen six innings when it looked like he’d be done for in the fifth, which was a victory in and of itself. But that was the only victory of the night for the home team. Holmes, who had given up only one home run all season prior to Wednesday, gave up two home runs while the Bucs and their bullpen shut down the Mets.

After a 15-minute delay to the start of the game, the rain started once again in the bottom of the first. The Mets loaded the bases on left-hander Bailey Falter, but Luis Torrens struck out to end the inning.

The rain picked up steadily in the top of the second. Holmes got the first two out before giving up a single to Isiah Kiner-Falefa. He had Matt Gorski on 0-2, and threw a slider that the first baseman laid off. It should have been strike 3, with the pitch landing in the glove of Torrens just below the top of the zone, but home plate umpire Carlos Torres ruled it a ball.

Holmes then threw a sweeper up. Higher than the slider, it could have been considered a borderline pitch, but it was ruled ball 2. Ball 3 was legitimate, nowhere near the zone. Gorski fouled off the sixth pitch to work the count full.

He didn’t miss on the second pitch, a sweeper over the heart of the plate. Pittsburgh went up 2-0 on Gorski’s second home run of the season.

Heading into the bottom of the second, the grounds

Pirates… page B-3 crew came out to dry the field. The rain started to taper off as the diamond dry was applied to the dirt and the game was paused for several minutes. When play resumed, Falter struck out the first two hitters he faced, then walked Jose Azocar and picked him off first base.

It was that kind of night for the Mets (28-16). They loaded the bases on Falter again in the fourth inning, but interim manager Don Kelly played it conservative by going to his bullpen for Chase Shugart to counter Azocar. Falter had only thrown 78 pitches, but with five walks, he wasn’t exactly showing strong control.

Shugart, a righthander, got Azocar to pop up to center field. The Mets managed only four hits off Falter and none were hit particularly hard. Shugart (2-3) and right-handers Tanner Rainey, Jared Bednar and Dennis Santana held them scoreless the rest of the way to help the Pirates (15-29) to just their third win this month.

Jared Triolo hit a tworun homer with none out in the fifth. Holmes then put two on before getting Joey Bart to ground into a double play.

Holmes (5-2) went six innings, allowing four runs on seven hits, walking one and striking out four, though one could make the argument that it could have been five.