WASHINGTON — Devin Williams should have had one out in the ninth inning Thursday, but a misread by his center fielder placed the Mets lead in jeopardy.

A.J. Ewing initially broke backward on Daylen Lile’s fly ball to center and upon recovery had to lunge for a ball that popped out of his glove for a leadoff double.

But Williams has dominated after a rocky transition to the Mets. And Thursday, he recorded three straight outs without Lile advancing beyond third base, securing a 2-1 victory over the Nationals.

It was the 10th straight scoreless appearance for Williams, who earned his seventh save in eight chances.

“I feel like I’m on a good streak here and I am trying to keep it going,” he said.

The right-hander credited a mechanical adjustment for his improvement over a rough April stretch in which he surrendered eight earned runs over four appearances.

“It’s basically my starting position — the way I am starting with my hands, it’s just a lot more comfortable for me,” he said.

Williams said during his struggles he was experimenting with a new starting position with his hands because of concern he was tipping his pitches.

But now he’s found a new comfort zone.

“I have a lot of reps coming from there, so it was always kind of a struggle for me coming set with my hands at my belt,” Williams said. “So we just changed it.”

The Mets have received strong work from not just Williams, but the back end of their bullpen overall. Huascar Brazobán, Brooks Raley and Luke Weaver are the other key components. The group, including Williams, combined for four scoreless innings Thursday.

“They are aggressive, they are attacking hitters, they are sticking to their strength,” manager Carlos Mendoza said. “A perfect example was in the ninth inning there with a runner on third base and less than two outs. Devin gets behind in the count and he sticks to the changeup there. He gets to 3-1, gets the swing and miss and then gets a strikeout. It comes down to them executing, but also sticking to who they are.”