Stephen Strasburg woke up Sunday morning with the longest losing streak of his short, brilliant career and a simple plan to break it. In the three straight starts he lost, he had moved away from his strength. Coaches implored him to throw more fastballs. Scouts saw him “pitching backwards” — throwing curves and change-ups before his fastball. “I wanted to really get back to the things that make me successful,” Strasburg said.

In the Washington Nationals4-0 victory at Marlins Park, Strasburg shut out the Miami Marlins for six innings and provided the keystone hit during the Nationals’ game-breaking rally. In one day, he lowered his ERA to 2.66 and raised his batting average to .385. On the mound, he dodged trouble and escaped jams, pitching around six hits and saving his strikeouts for key moments.

After Tyler Clippard wiggled out of a bases-loaded, no-outs jam in the ninth inning, Manager Davey Johnson walked into the small weight room in the visitors’ clubhouse where Strasburg was working out. Johnson congratulated Strasburg on the performance, an uncommon move for him.

Strasburg has surely had more dominant outings, but Johnson raved about how Strasburg relied on his fastball. He threw 70 of them in 105 pitches. He let his arsenal revolve around the fastball rather than trying to trick batters. He got back to the things that make him successful.

“I have to say, that was one of the more impressive games that Stras has pitched,” Johnson said. “I thought he used his fastball better. I thought his location was a little better. That’s the kind of Strasburg that I know and love.”

Ozzie Guillen, the Marlins’ volatile manager, provided an odd sideshow when he screamed obscenities at Bryce Harper after a spat about the amount of pine tar on Harper’s bat. Harper got the last laugh, squeezing the final out of the game in foul territory after a collision with Steve Lombardozzi. (Both players walked away no worse for the wear.)

For the first time since April 19, the Nationals played without shortstop Ian Desmond, who sat with a left oblique strain. They leaned on their pitching. In the first three games after the all-star break, Jordan Zimmermann, Gio Gonzalez and Strasburg have combined to allow two runs in 18 innings while striking out 22 batters.

Before Sunday, pitching coach Steve McCatty had drilled into Strasburg the importance of establishing his fastball and throwing it more in unpredictable counts. Of Strasburg’s seven strikeouts, three came when batters took a fastball for strike three, frozen by the speed and precise location.

“The thing about Stephen is, his off-speed is so good that it’s easy to fall back on that,” McCatty said. “But his fastball still is an outstanding pitch. So we just talked about it. We’ve been talking about it and talking about it and talking about it — get back to using it.”

Strasburg peppered the zone, throwing 70 strikes, and kept his fastball mostly in the 95-96-mph range. Strasburg had only two 1-2-3 innings, his first and his last. He ended his outing with a 96-mph fastball for a called third strike to John Buck.

“It’s just a mind-set,” Strasburg said. “I just want to go out there and just throw it to the glove and trust it.”

The Marlins still had chances all game, and their best opportunity came in the third, when Strasburg faced a bases-loaded, one-out jam. He struck out cleanup hitter Logan Morrison, freezing him with a 96-mph fastball at the top of the strike zone.

Hanley Ramirez followed with a sharp grounder down the third base line. Ryan Zimmerman made a diving, backhanded stop and whipped a sidearm throw across the diamond that sailed to the inside of first base. Adam LaRoche shuffled his feet, allowing himself to stretch all the way across his body and keep his foot planted on the bag. The stretch made the inning-ending play, even more than Zimmerman’s stop.

“He’s definitely one of the best, if not the best,” Zimmerman said of LaRoche. “You know you kind of just have to get it over there in the vicinity. He gives you a lot of confidence.”

The Nationals did not record their first hit against Ricky Nolasco until the fifth inning, when Michael Morse, who went 2 for 4 with an RBI, led off with a single to left field. With two outs and Morse on second, Guillen intentionally walked Jhonatan Solano, the Nationals’ backup catcher, to face Strasburg.

The rote strategy of bringing the pitcher to the plate does not account for a pitcher like Strasburg, who entered hitting .360. “I couldn’t do it, because I know him,” Johnson said. “I know what kind of hitter he is and how much pride he takes in his hitting.”

Nolasco showed him uncommon respect, twirling a first-pitch curveball for strike one. Strasburg stepped back, smiled and shook his head. After another curve for a ball, Nolasco fired a fastball. Strasburg smacked it through the right side of the infield, raising his slugging percentage to .654. His on-base percentage, in 31 plate appearances, shot to .448.

“I mean, there’s no expectations,” Strasburg said. “So that’s the easy part. You just have to go up there and make him work, and if he makes a mistake, just do your best to put the fat part of the bat on the ball.”

Strasburg has been trying to make his approach on the mound just as simple. Despite his all-star stature, he remains a 23-year-old who spent six weeks in the minor leagues and has 35 major league starts under his belt.

Now at 105 innings for the season, he likely has about 10 starts remaining until the Nationals (51-35) shut him down for the season, their effort to decrease the risk of injury in his first full season after Tommy John surgery. Between then and now, he will figure himself out more, and realize that sometimes the simplest way is best.

“This is an awful tough level to learn at,” McCatty said. “He’s going to have his moments and his games where we might see things that he doesn’t necessarily see. . . . He’s still learning at this level. He’s got a long way to go. It’s not a finished product by any means. But it’s still an awful good one.”