No one looked more dejected than Pete Alonso.

And no one could find a way to change that expression either, no matter the encouragement offered.

Alonso faced a challenging situation on Thursday night when he witnessed Kodai Senga fall to the ground due to a right hamstring strain. This incident occurred after the first baseman made a throw during the Mets’ 4-3 victory against the Nationals.

In the top of the sixth inning, Luis García Jr. hit a grounder off the first base line, which Alonso chased down.

He timed the throw correctly to a running Senga, but it was too high.

The righty had to leap in the air for the grab, and he landed his right foot on the base for the out.

Nevertheless, Senga immediately grabbed his right hamstring in pain and fell to the ground, unable to continue his stellar start.

Carlos Mendoza told Alonso that Senga said he felt something in his hamstring during the stride before making the catch and landing on the bag.

Yet, it didn’t matter to the four-time All-Star.

It still weighs on him.

“I still feel awful because, for me, just trying to make a baseball play. Just trying to make a play for my pitcher,” Alonso said after the win. “I tried to make the best throw I could. It just sucks. I mean, sucks to be involved in that. Senga, he’s one of our guys here and it sucks. You hate to see anyone go down. And yeah, it sucks being a part of that. … I wish it wouldn’t have turned out like that.”

Alonso has had some defensive slipups this season.

He had a costly one in May that led to an 8-2 loss at Yankee Stadium when his wild throw home during a tie game allowed Jasson Domínguez to score the go-ahead run in the eighth inning.

“I mean, he’s a pretty good runner [García] so I was just trying to just get rid of the ball as quick as I could and as accurately as I could,” Alonso said. “The throw was good because it was over the base but obviously too high. He made an unbelievable play.”

Alonso’s throws have become a work in progress, and a few teammates surrounded him following the play.

Francisco Lindor and Brett Baty patted him on the back with their gloves.

It didn’t make a difference for Alonso.

“I’m appreciative of their support for sure. But I mean, it still doesn’t change the fact of the result of the play,” he said. “I mean, yeah, OK, whatever, we got the out, but at what cost? So, yeah, it doesn’t feel good. I know it’s the innocence of just trying to make a play and obviously things happen on the baseball field, but obviously just wish it didn’t happen that way.”