WASHINGTON — Brad Stevens stressed decompression yesterday.

His team had just been whacked, blown away by a 22-0 Wizards run in the first quarter of Game 3, and the Celtics coach made team workouts optional.

“I hope some of them walk around D.C. and take a deep breath,” he said during a conference call yesterday.

He needs a team that’s back on the balls of its feet, instead of back on its heels, and the Celtics have yet to begin a game against the Wizards that way. The Wizards are averaging 39.7 points in the first quarter this series, including a 42-pointer in Game 2.

That inability to land the first punch finally caught up with the Celtics in Thursday’s Game 3 loss, when the Wizards managed to lock up the game with a 22-0 run.

In their 593 playoff games all-time that preceded this series against the Wizards, the Celtics allowed 38 or more points in the first quarter 10 times, according to stats guru Dick Lipe.

In the first three games against the Wizards, the Celtics have allowed 38 or more each time. These are record times, and as Stevens has pointed out, this has simply been how the Wizards impact opponents.

Especially the Celtics, though.

“No question that has been a major issue against them for most teams,” said Stevens. “But the main thing is to stop talking about it and do it. They kicked our butt.

“They did everything better — it was not even close. All the way down the line they were better than us.”

Though slowing down John Wall would seem to be the main goal, it rarely happens that way for the Wizards point guard across the league. And he was able to put pressure on Isaiah Thomas so thoroughly, the Celtics point guard never had a chance to establish himself offensively.

Wall was also able to start fast thanks to the Celtics’ first-half turnover problem, with a flummoxed Marcus Smart accounting for six of the team’s 10 first-half turnovers — lighter fluid for Wall, the fastest man in the NBA.

“You can’t turn the ball over,” said Stevens, “because then he gets going in transition. We were a little better against him in the second half with our pick-and-roll defense, but they killed us in transition and on the glass.

“Wall and (Bradley) Beal are great players. And it’s hard enough to beat them when you have five guys who are back and set defensively. It’s harder when you end up scrambling all over the place.”

It’s also harder when a team loses its composure, which Avery Bradley admitted was the case in a game that featured eight technical fouls, including one for each coach, three ejections and one Flagrant 2 foul — the latter when Kelly Oubre Jr. charged and shoved Kelly Olynyk to the ground following an illegal pick by the Celtics center.

Though Stevens clearly needs his team to make better decisions — Terry Rozier’s shove of a baiting Brandon Jennings was another example of a bad reaction — he was actually happy that the situation didn’t get worse.

The possibility remained yesterday that Oubre could face suspension for the nature of the foul.

“When Oubre ran at Kelly, I thought at both ends that cooler heads prevailed,” said Stevens. “The league makes the next call, but I don’t think (the incident) had anything to do with the outcome.

“We just have to focus on playing better basketball.”