Gio Gonzalez is met at the mound by catcher Kurt Suzuki and Nationals pitching coach Steve McCatty during a rough first inning. (Toni L. Sandys/The Washington Post)

The Washington Nationals returned to the refuge of their clubhouse Sunday afternoon after a nine-inning boot to the teeth, heartened only by the fact that for the next few days the Atlanta Braves will be somebody else’s problem. The Braves came to Nationals Park for a weekend showdown, and they left an early rebuke to the unified chorus picking the Nationals as favorite to defend their National League East title.

Lackluster in every way the game allows, the Nationals absorbed a sweep-sealing, 9-0 demolition at Nationals Park. Their bats managed four hits against left-hander Paul Maholm, Gio Gonzalez endured the worst start of his Washington tenure, Ryan Zimmerman committed his third throwing error in three days and their bullpen yielded two more runs. Their flight to Miami for a three-game series against the lowly Marlins could not leave soon enough.

“I don’t think they took us by surprise at all,” center fielder Denard Span said. “We knew they were a good team coming in here. They came in and gave a good, old-fashioned kick in the butt.”

For the second straight day, the Nationals dealt with a potentially more harmful loss. In the second inning, a few hours after catcher Wilson Ramos landed on the disabled list with a strained left hamstring, second baseman Danny Espinosa took an 88-mph fastball from Maholm off his right hand. Espinosa hopes to return Monday after X-rays came back negative. Sunday, he left in the fourth inning in favor of Steve Lombardozzi.

By the middle innings, Manager Davey Johnson started to pull other starters by choice, the game already well out of the Nationals’ reach. The Braves pounced on Gonzalez for three runs in the first inning, and Andrelton Simmons’s home run in the third gave the Braves a 7-0 lead before they had recorded their eighth out.

“It’s just early,” Johnson said. “Things happen for the best. We should’ve won the first [game of the series]. We were right there on the second one. We just got waffled today. I don’t put too much stock in it.”

The Nationals (7-5) knew the defense of their NL East crown would not come easy, and with 150 games remaining their World Series aspirations remain intact. But it did not have to look so hard so soon. The Nationals have lost by scores of 15-0 and 9-0, and they already trail the 11-1 Braves by four games in the NL East.

“You can’t just judge a team on the first 12 games,” Gonzalez said. “It’s impossible. You’ve got to give us a chance. Our job is to make sure we stay afloat and keep playing, turn this around and go into Miami with a new attitude.”

The Braves, even missing catcher Brian McCann and first baseman Freddie Freeman, overpowered the Nationals all weekend. They outscored them 18-5, outhit them 29-16 and made three errors to the Nationals’ four. The Nationals scored four runs in the first two innings Friday night, and then the Braves held them to one run over the next 26. Atlanta even managed to cool down Bryce Harper, who homered in his first at-bat of the series and went hitless in his final nine with four strikeouts and two walks.

“I still don’t think that they’re better than us,” Espinosa said. “They’re hot right now. They’ve come back on people. They’re playing well. It doesn’t last forever. I’m not worried about it. I’m going to be real confident going into these next 16 games” against the Braves.

“They put their best foot forward,” shortstop Ian Desmond said. “We didn’t.”

In Gonzalez, the Nationals sent to the mound the right starter to halt the start of a losing skid. But from the first pitch, a fastball B.J. Upton smacked into the left field corner for a double, Gonzalez was not his usual self.

“Wasn’t attacking the strike zone, leaving every pitch up, falling behind on a good-hitting team,” Gonzalez said. “That’s all it was, just falling behind and giving these guys too much to come back.”

He walked two hitters in the first inning, constantly gritting his teeth and shaking his head. He fell behind hitters and left pitches up. Pitching coach Steve McCatty trudged to the mound for a lengthy chat. Chris Johnson provided the key blow of the first, a two-run single on an 0-2 curveball Gonzalez left over the plate that made the score 3-0.

Gonzalez recovered in the second inning, but the Braves hammered him again in the third. Even when he loses control, Gonzalez rarely allows opponents to hit him hard. Last year, he allowed homers with less frequency than any other major league pitcher. In the third, Justin Upton led off with a home run to right field, his seventh of the year, on a 2-2 curveball. After a walk and a single, Simmons blasted his own homer to left field. The Braves led by a touchdown. Gonzalez raised his glove to the umpire, the universal sign to request another baseball, before Simmons had passed second base.

“The Braves right now are running hot,” Gonzalez said. “They’re hot right now and you’ve got to give them credit. As a pitcher, you have to go out there and try to keep that to a minimum, especially to give these guys a chance to swing the bat. And I didn’t do that today, obviously. I take the blame on this one, 100 percent. I didn’t give these guys a chance to swing it or do anything today.”

Maholm, meantime, showed why he has not allowed an earned run all season. He mixed location and speed like a maestro, even starting Desmond with a 62-mph curveball. (“Disgusting,” Desmond said, as a compliment.) All four of the Nationals’ hits off him in 72 / 3 innings were singles, two of them from Kurt Suzuki.

“He changes his arm angle a lot,” Span said. “It’s hard to pick up the ball. All his pitches move. He executed all his pitches today. You could tell he had a game plan, and he stuck with it.”

The Nationals figure to find a more hospitable opponent in the two-win Marlins, a team they swept to start the season. They departed Washington on Sunday evening knowing they had improvement to make, in every area. But they also knew they had time.

“We know we’re not playing our best,” Desmond said. “So I guess we learned that. But it’s April. Fortunately for us, there’s a lot of games left.”