Stephen Lombardozzi is greeted by teammates after scoring in the sixth inning. (Greg Fiume/Getty Images)

Monday night, in his first start this year at Nationals Park, Stephen Strasburg found himself in an unfamiliar position. He walked into the dugout concerned he had tipped pitches and let the Houston Astros know what was coming. He had just lost the lead. He needed one of his teammates to pick him up.

With the bases loaded, two outs and the score tied in the sixth inning, the game’s biggest moment fell to the Washington Nationals’ most unlikely candidate. Stephen Lombardozzi started the game only to give second baseman Danny Espinosa a night off, a “mental break,” Manager Davey Johnson said.

Lombardozzi, 23-year-old rookie from Atholton High who spent the winter lifting weights at Nationals Park, capped just the eighth start of his career with a two-run bloop double. His fourth hit of the night saved Strasburg’s start and provided the fulcrum for a 6-3 victory over the Houston Astros.

“I won’t forget this night,” Lombardozzi said. “It was pretty awesome. And to do it here, at home, was pretty special.”

Before 16,245, the smallest crowd to watch him pitch in his 12 home starts, Strasburg gave up two runs in six innings, which actually raised his ERA after three starts to 1.42. He struck out five, walked one and gave up six hits, all singles. He laid waste to the Astros for five innings with one of his best curveballs.

A 32-pitch, two-run sixth ended his night.

When he retreated to the dugout, Strasburg planned to watch film of his start to determine if and how he had tipped his pitches. He suggested the Astros had gained an advantage by using runners on second base to pick up signs.

“When guys would get in scoring position I felt like they definitely were kind of seeing pitches a little differently,” Strasburg said. “I don’t think I was throwing any pitches worse or with different kind of movement, but they definitely seemed a little bit more comfortable with guys on second base. . . . I know what it is and I know how to fix it, so that’s the bottom line.”

Rather than the Nationals’ ace pitcher deciding the game, their greenest hitter seized it. Lombardozzi entered Monday with 42 plate appearances between his September call-up last year and limited playing time as a utility man this April. In his spot start, Lombardozzi went 4 for 5 with two of the Nationals’ biggest hits.

Lombardozzi made the Nationals this spring training, convincing them his versatility and consistency would be worth sacrificing his development at Class AAA Syracuse. The Nationals knew Lombardozzi would stop playing every day for the first time as a professional, which has been an adjustment.

“I’ve been loving being up here with these guys. It’s been fun,” Lombardozzi said. “But you also get that itch. After you watch a couple of games, you want to get out there.”

Lombardozzi sparked the Nationals’ first run after he dropped a bunt single in the third inning that scored Ian Desmond from second after Astros starter Kyle Weiland threw the ball into right field. In the sixth, the half-inning after the Astros had tied the score at 2, Lombardozzi fell behind 0-2 to Weiland.

Lombardozzi, a switch-hitter batting left-handed, took a curveball in the dirt and then flicked a fastball to left field. The ball plopped along the foul line and allowed Rick Ankiel and Roger Bernadina to score.

Once he reached second, Lombardozzi clapped his hands, then looked at Desmond and third base coach Bo Porter and cracked up.

“It wasn’t pretty,” Lombardozzi said. “But I was able to dump it down the line there.”

Ryan Zimmerman followed with a two-run single, which further cemented Strasburg’s win. Five days prior, in New York, Strasburg threw 108 pitches, setting a career-high. He erased any questions about how he could respond to the workload.

Strasburg navigated the first five innings mostly with his sinker and curveball, which he had made an adjustment with in the bullpen before his start in New York, overthrowing less and trusting the pitch more. Typically, breaking balls come back last after a pitcher returns from Tommy John surgery.

“It’s getting better to what it was in college — not only be able to throw it for a strike but also throw it for a swing-and-miss pitch,” Strasburg said. “I’m not expecting it to be perfect every day, but it’s about making adjustments. I have a much better idea of what I need to do to correct it when it isn’t right.”

In the first five innings, the Astros pushed only one base runner past first base and none past second. Strasburg cruised into the sixth having thrown 61 pitches.

The third time through the lineup, though, the Astros mustered a rally, loading the bases with no outs on two singles and a walk. Pitching coach Steve McCatty visited the mound to calm Strasburg. Carlos Lee flied to intermediate center field, and Ankiel made an incredible throw, a strike to Wilson Ramos’s chest from about 310 feet away that held Schafer on third. The crowd gave the non-out at the plate a standing ovation.

“I would have called it a strike, that’s for sure,” Strasburg said.

With one out, Strasburg struck out Travis Buck, swinging at and missing a 2-1 change-up and then a 95-mph fastball. The crowd, small in number, rose and roared — Strasburg was actually going to escape this jam. But Chris Johnson, after fouling away a 96-mph fastball, roped a 97-mph heater to right field. The single scored two runs, tied the game and sucked the life out of Nationals Park.

One half inning later, Lombardozzi pumped life back into it. After the game, as Lombardozzi gave an on-field television interview, Jayson Werth drenched him with a bucket of orange Gatorad. “I didn’t see it coming,” Lombardozzi said. “It was pretty cold.”

He knew the moment would not last. Even after Lombardozzi’s four hits, Johnson never had any question about who would play second base Tuesday night. Lombardozzi will return to the bench. “As much as I like him,” Johnson said, “Espi’s my second baseman.”

Lombardozzi could accept that. He will always remember Monday night, the game he bailed out the Nationals’ ace.