Jon Niese expressed surprise the New York Mets and Washington Nationals sloshed through Wednesday night’s game at Cit Field in what at points was a driving rainstorm.

“I was wondering what the hell we were doing out there,” the southpaw acknowledged.

Left fielder Jason Bay took a more pragmatic approach.

“I live in Seattle, so that’s a summer day right there,” Bay said, half-seriously. “… Growing up in the middle of nowhere Canada, and Washington, the drainage isn’t great, so you just deal with it.”

The Mets weathered Wednesday’s conditions, getting seven scoreless innings from Niese in a 3-0 victory over the Nationals. They still must navigate the next few weeks minus some key components.

With David Wright joining Ike Davis and Angel Pagan on the disabled list, Justin Turner moved from second to third base and Ruben Tejada made his season debut at second.

Turner, who opened the season at Triple-A Buffalo, continued his solid production. His two-run double off Nationals left-hander Tom Gorzelanny in the sixth inning opened a three-run cushion as the Mets drew even with Washington for fourth place in the division at 20-22.

Niese also stepped up. After wilting late in his outing in Colorado and getting charged with five runs in 6 1/3 innings, Niese this time buckled down. In the driving rain, the Nationals had loaded the bases with two out in Niese’s seventh and final inning on an infield single by pinch-hitter Brian Bixler.

Terry Collins stuck with Niese, who fell behind Roger Bernadina with three straight balls. Niese, primarily throwing fastballs because that offered his best chance at controlling the slick baseball, rallied to get a full count. After a pair of foul balls, Niese then got Bernadina to ground to first baseman Daniel Murphy, who made the play in the sloppy conditions.

“I’ll tell you what, the playing surface, it was wet and there were some puddles out there, but it really played really well,” Murphy said. “You could still hold your footing pretty well. I tested it out every couple of pitches to make sure I could still break. I never felt like I was in danger of slipping too bad out there.”

Said Niese: “Especially in those conditions I knew he was going to take until he got two strikes just because of the conditions that were out there. Fortunately I battled back and I threw a cutter that he rolled over, and Murphy made a great play.”

Collins expressed satisfaction Niese battled through the conditions and overcame the baserunners. The Mets have limited margin for error with all the big bats out of the lineup, and desperately need efforts such as Wednesday’s scoreless performance from Niese to offset the absences.

“I don’t think there’s any question we’ve got to pitch,” Collins said. “And I don’t care how good your lineup is, you’ve got to pitch to win. Right now, with the middle of our lineup shaken up a little bit, we really have to pitch. We’ve got to keep ourselves in ballgames, which we have the last two games.”

As for Niese, he could never recall pitching in such sloppy conditions.

“That’s the wettest I’ve ever been pitching,” the southpaw said. “Every ball the umpire gave me was just soaking wet. I just kept trading it out until I got a dry one. Even then it was still kind of wet. It was tough to get a grip on the ball, but I made sure the ball was dry before I pitched. In that situation you’ve just got to make sure you throw whatever you can for a strike. I felt the fastball was that pitch.”