Nationals catcher Jesus Flores high-fives Tyler Clippard after the right-hander closed out Washington’s 6-5 comeback victory over Arizona, the team’s eighth win in a row and 12th victory in its last 13 road games. (Matt York/Associated Press)

Something about these Washington Nationals has changed. They have morphed from a compelling bunch, a feel-good story that could fade away, into the most lethal team in baseball. They were ascendant when they relied solely on the game’s best pitching staff. Now they have a deep lineup to match, an offense that can erase a deficit at a moment’s notice. Now they are dangerous.

The Nationals flaunted their newfound pop in a 6-5 victory Saturday over the Arizona Diamondbacks, their eighth straight win and 12th out of 13 on the road. The Nationals limped into the middle stages Saturday night trailing by a fistful of runs, starter Edwin Jackson searching and their winning streak at peril. Their offense once rolled over. Now they wear you down and knock you out.

After they entered the fifth inning down, 4-1, the Nationals erupted with five runs and chased left-hander Wade Miley, a top Rookie of the Year candidate, before he could survive the inning. An RBI double by Jayson Werth. A two-run single by Ryan Zimmerman. A double to right-center by Michael Morse. The line kept moving.

“Right now, we can afford to have games like today,” first baseman Adam LaRoche said. “We can have our starter out there grinding through without his best stuff, and still pull away with the win. I got to think in the first couple months, when we ran into a game like this, we were losing it.”

The Nationals took control in the five-run fifth inning, and they spent the rest of the game holding on. Tom Gorzelanny, Ryan Mattheus, Michael Gonzalez and Tyler Clippard embarked on an epic bullpen adventure. They pitched 3 1/3 scoreless relief innings, with each of the first three relievers stranding the tying run in scoring position. Clippard made it easy in the ninth with three outs in five pitches.

The relievers’ performance underscored a hidden key to the Nationals’ win streak. Manager Davey Johnson has interchanged roles in the bullpen to keep them fresh, and they possess the depth and talent to still hold leads. With Drew Storen and Sean Burnett unavailable, Johnson used Gonzalez to set up and did not miss a beat.

“The way everybody is out there pitching, you could put anybody in that situation,” Gonzalez said. “You could put whoever you want. That’s how confident the bullpen is right now. . . . I really feel like this bullpen, you just don’t mess with it.”

The Nationals are 10-0 since in games Werth has played since he returned Aug. 2 from a broken wrist. Werth, who batted leadoff Saturday for the first time this year, has gone 14 for 34 with seven walks and four doubles. His return lengthened a lineup reaching its full potential. Ian Desmond still has to return from an oblique strain; Saturday afternoon he took 30 swings in the batting cage. But in games Werth has played this season, the Nationals have averaged 5.6 runs.

“This makeup of this lineup is totally different,” Johnson said. “It’s in attack mode. We’re not up there defending like a goalie. We’re up there trying to do some damage. It’s fun to watch. I tip my hat to [hitting coach] Rick Eckstein.”

The Nationals’ latest assault may have left the Atlanta Braves wondering what they’ve got to do. The Braves have won 14 of their past 17 games. They have the third-best record in the National League. The Nationals’ lead in the NL East remains 4 ½ games, the same as it was July 24.

Johnson has been waiting for the win that would ensure the Nationals could conclude the season playing .500 ball and still win 95 games. It came Saturday. The Nationals are 71-43, the best record in the majors. If they go 24-24 over the final month and a half, they will finish with 95 victories.

“The confidence is at an all-time high right now,” Mattheus said.

In their latest win, Zimmerman gave Jackson an immediate lead with a run-scoring double in the first. But Jackson labored through the first three innings, throwing 63 pitches and allowing at least a run in each inning. His tempo slowed between pitches. He was not quite himself.

Miley, who entered with a 2.85 ERA, cruised through the first four innings. The fifth started innocently enough with a bunt single by Steve Lombardozzi and a sacrifice bunt from Jackson. The trickle turned into an explosion.

Werth smashed a double to right-center, his second hit of the game. Danny Espinosa chopped to third base, a tricky play that allowed him to reach on an error. Zimmerman scored them both with a single. Morse crunched a double. LaRoche walked, the final straw for Miley. Jesus Flores ended the scoring with a soft liner up the middle. At one point, seven consecutive hitters who tried to reach base did.

“When you’re getting production from one through nine in the lineup, it’s a good team,” Morse said. “You never know who’s going to win the game for us that day.”

The bullpen carried the final portion. Johnson summoned Gorzelanny with the Nationals up, 6-5, with two outs in the sixth. He struck out Stephen Drew to hold the tying run on second.

Each reliever had a similar cross to bear. Mattheus entered with one out in the seventh and Aaron Hill on second base. He induced grounders from Paul Goldschmidt and Justin Upton, the Diamondbacks’ best two right-handed hitters. Mattheus pumped his fist on the way off the field.

“Sometimes, I get a little worked up in big situations like that,” Mattheus said. “I’m learning to use it to my advantage.”

Johnson gave the eighth inning to Gonzalez. He walked two batters and fired three balls to another. But he, too, escaped with a strikeout, fooling Drew with a slider in the dirt. Even when he was wild, it was by design.

“You know what guys can hurt you, you know what guys can’t,” Gonzalez said. “I was just being careful with it. Today, I can honestly say it was one of those days when I had nothing. So I kind of threw the kitchen sink today.”

Clippard handled the ninth in a breeze, three straight flyouts. Bryce Harper, who had come off the bench in the seventh, squeezed the final out in center field. The Nationals had won another, and no one lately has figured out how to stop them.