About 20 minutes after the Washington Nationals’ 4-3 loss to the Arizona Diamondbacks on Saturday at Nationals Park, reliever Austin Adams sat at his locker, looking at his phone with his elbows on his knees, which were still covered in the black tights he wore under his uniform as he walked in the go-ahead run in the 10th inning.

When he saw reporters heading his way, he put his phone away and stood up, waiting for the cameras to slide into place. As they did so, he made eye contact with the reporters, who asked him why he walked one man to load the bases, then another to score a run.

“Well,” he said. “This isn’t fun.”

No three words better sum up the Nationals’ experience this April.

Neither Adams’s walks nor the gaffe that Manager Dave Martinez made as he summoned Adams in the first place nor Ryan Madson surrendering the lead in the eighth nor missed chances to add to that lead in the sixth and seventh can earn all the blame for why the Nationals fell for the 16th time in 23 games.

Not one of those issues, from Martinez’s mistake to his relievers’ struggles, from the lineup that can’t seem to produce enough runs to a bullpen that always seems to need more of them, is the lone reason this team is five games under .500 at 11-16. These Nationals are 1-8 in one-run games, a record that has rendered “being close” an inadequate form of consolation.

This Nationals season has five months to go. The first month, at least, has not been much fun at all.

“I got nothing to say except for those guys are playing with heart,” Martinez said without animosity — but without answers, either. “We just have to keep going. I told them all after the game: ‘Keep fighting. It will change.’ ”

Like Adams, Martinez had to answer for a mistake that ultimately cost the Nationals, both coming in the 10th inning.

Now, in fairness to Martinez and Adams and all those who skip to the end, the Nationals should not have needed 10 innings at all. In a game started by Diamondbacks standout left-hander Patrick Corbin and Nationals fifth starter Jeremy Hellickson, Washington led after five innings because Hellickson mixed and matched to perfection. He threw 57 pitches in 5⅓ innings — just 14 of them balls.

Ryan Zimmerman, whom Martinez moved to the second spot in the order in hopes of sparking a hot streak, gave Hellickson a two-run lead with a homer in the third. Hellickson made that lead stand up until the sixth, when David Peralta hit his second solo homer of the game to tie it. Howie Kendrick homered to give the Nationals another lead in the bottom half, and the lead was in the hands of the bullpen, right where the Nationals wanted it.

But when they put men on later in the sixth and in the seventh, the Nationals could not add to that lead. When Madson took over for the eighth, he could not hold the one-run lead, surrendering a two-out, game-tying single to A.J. Pollock. Madson did not answer questions after the game, which is not like him. He did not appear to have any health issues.

So a game the Nationals could have won headed to the 10th inning, and that is where Martinez erred. Sammy Solis started the inning, and he allowed a double and a walk around one out, at which time left-handed-hitting Jarrod Dyson was due to hit with two on and the go-ahead run at second.

Adams had been warming in case the Diamondbacks opted to go with a right-handed pinch hitter ahead of the right-handed-hitting Pollock. When Martinez saw right-handed Chris Owings step into the on-deck circle, he walked out of the dugout and pulled Solis for Adams.

Unfortunately, the Diamondbacks had not yet announced Owings was pinch-hitting. Martinez explained later that he was looking at his lineup card, and he looked up quickly to see home plate umpire Nic Lentz looking at his, too. He assumed Lentz was noting the pinch hitter.

What Martinez didn’t realize was that Kendrick had jogged in from second base to talk to Adams, and Lentz was noting a mound visit on his card — not a pinch hitter.

“I completely take ownership to that,” Martinez said. “It will never happen again, because I will make sure I look right at him and say, ‘Is he in the game?’ ”

The move left Adams facing Dyson, who walked to load the bases. He walked Pollock, too, and the go-ahead run scored. Adams said the matchup didn’t matter.

“I have to go out there and throw strikes. That’s what it comes down to,” he said. “I didn’t do my job. I didn’t get ahead of hitters.”

Zimmerman praised Martinez for his honesty about the mistake and for his positive message after the loss. He also acknowledged the complicated nature of baseball causation.

If Adam Eaton or Anthony Rendon or Daniel Murphy were healthy, perhaps the Nationals score enough runs that the game never gets to Adams. If Madson does his job as he normally does, the game probably ends sooner. If any of the Nationals’ hitters could have tacked on a run . . .

“Everyone can do better. It’s not one thing,” Zimmerman said. “Just got to keep going.”

More on the Nationals and MLB: