Nationals center fielder Trea Turner is unable to pull down a fly ball hit for a double by Baltimore’s Matt Wieters during the fifth inning. Washington lost, 10-8. (Nick Wass/Associated Press)

On Wednesday afternoon, Washington Nationals Manager Dusty Baker was asked whether possessing an eight-game cushion in the National League East in late August altered how the Nationals were navigating the schedule and resting players. Baker said it was no time ease off the gas.

“I’d like to pad this lead,” Baker said. “Ain’t nobody scared of who’s behind them, but I’d like to pad it.”

Baker elaborated, emphasizing he believes the Nationals haven’t peaked yet because the offense hasn’t featured its most potent pieces mashing in unison for a sustained period. There is ample time for Baker’s vision to crystallize, but it didn’t in the Nats’ 10-8 loss to the Baltimore Orioles, their sixth straight to their American League neighbors and fourth straight overall. And yet the manager emerged encouraged following a five-run ninth inning rally that included wounding the Orioles’ previously untouchable closer.

“I just know that we’re starting to swing the bats,” Baker said. “I can feel it. I can feel in my heart that we’re going to get hot.”

For eight innings, the Nationals were outclassed, prolonging a recent trend of sloppiness. The four-game losing streak isn’t Washington’s longest (the team dropped seven straight in June), but these Nationals (73-53) had never looked quite as overmatched as they did Tuesday in Baltimore and for most of Wednesday’s game.

Tanner Roark, the Nationals’ most consistent pitcher, was atypically wild over the first couple innings and lasted just five. The defense, so reliable until last week, continued floundering. Two errors hiked Washington’s total to 12 over the past seven games.

The offense, with its full cast of characters, created plenty of opportunities behind leadoff hitter Trea Turner, who had hits in his first four plate appearances Wednesday to match the club record with eight straight hits before striking out in the ninth. But the Nationals stumbled in important moments until they erupted in their final at-bat, when the game was already out of hand. Washington stranded two runners in the sixth and seven innings — the sixth-inning failure developing after the runners were on second and third with none out — and stranded two more in the ninth as it ran out of gas to end the game.

The bullpen, burdened over the past week, crumbled, rendering the Nationals’ ninth-inning outburst, which included Daniel Murphy’s first career grand slam and the first earned run Orioles closer Zach Britton had yielded since April 30, moot.

Attempting to establish himself on the inside half of the plate, Roark saw his 29th pitch strike Jonathan Schoop on the right elbow. The mistake loaded the bases and coaxed pitching coach Mike Maddux out of the dugout. It was the first inning, and Roark had recorded one out. It was a strange sight for the pitcher who has emerged this season to post the lowest ERA in the Nationals’ sterling starting rotation.

Roark’s 30th pitch walloped Matt Wieters squarely on the backside to score the third of the four runs the Orioles tallied in Roark’s 39-pitch first inning. The four runs were more than he had allowed in any of his previous five starts. It would have been worse if not for Trea Turner robbing Adam Jones of extra bases — the novice center fielder making a diving catch at the warning track for the game’s first out before the Orioles strung together three hits in a row, including a two-run home run from Manny Machado for the first of his four hits.

That Roark left having given up just five runs was a minor miracle. He hit three batters, walked three more and yielded seven hits. The Orioles left eight runners on base in five innings against him.

“He’s usually obviously not as erratic as he was tonight,” Zimmerman said. “He can’t be great every single time.”

The performance kept the Nationals in the game, though, and Danny Espinosa smacked a solo home run, his 20th, just over the left-field wall to trim the fifth-inning deficit to three. An opportunity for a flurry spawned in the sixth. After Murphy lined a leadoff single to right field, Bryce Harper slammed a hard groundball to first base that bounced past Chris Davis. Murphy aggressively took third base, just beating Davis’s throw, and Harper ended up at second.

The sequence chased starter Wade Miley, and Mychal Givens was Orioles Manager Buck Showalter’s choice to face Anthony Rendon, Wilson Ramos, and Ryan Zimmerman. Givens’s appearance started with striking out Rendon and then with him pumping his fist off the mound, having punched out Zimmerman on three pitches to retire the threesome in order.

The theme emerged again in the seventh. A run had already crossed the plate on Murphy’s two-out single to right field off lefty side-armer Donnie Hart when Harper stepped to the plate. Harper went down 0-2, laid off three pitches in the dirt and eventually struck out to end the threat.

The Orioles completed their outburst with five runs off Blake Treinen in the eighth inning, punctuated by a two-run home run by Wieters.

That homer was the difference, as Washington’s offense finally came to life in the ninth. After Murphy’s grand slam off right-hander Parker Bridwell, Harper slapped a one-out single to left field off the left-handed Britton. Rendon followed with a double to score Harper. Ramos then reached when Britton unsuccessfully tried to get Rendon at second base on a groundball to the pitcher.

With runners at first and second, Zimmerman stepped to the plate. He swung at the first pitch, a 96-mph fastball, and made hard contact, but the connection produced a groundball right at Schoop, who initiated a 4-6-3 double play to halt the improbable comeback attempt.

“If I got that pitch again, I’d do the same thing,” Zimmerman said. “I’d swing first pitch. It’s just unfortunate.”

It also sealed a fourth straight loss, which cut Washington’s division lead to seven games, but gloom did not fill the Nationals clubhouse. They viewed the ninth-inning outburst as a sign of what they’ve been expecting for months, a springboard to reach that elusive peak.