Adam LaRoche hits an RBI double to tie the game in the top of the eighth inning. The first baseman plated the go-ahead run with an RBI single in the ninth. (David J. Phillip/AP)

The gulf between their talent and their results in 2013, many of the men who run the Washington Nationals believed, rested in their inability to churn out one run when they absolutely, desperately needed it. They wanted to keep scoring in bunches when possible, but improve during the moments that call for a solitary, night-changing, season-shifting run. Tuesday night at Minute Maid Park, against the lowliest team in the major leagues, the Nationals needed one run.

In the Nationals’ 4-3 victory over the Houston Astros, Adam LaRoche delivered the game-tying double in the eighth and the go-ahead single in the ninth. But the prelude to LaRoche’s liner up the middle may have pleased Manager Matt Williams the most. In the ninth inning, the Nationals eschewed might and squeezed out the game-winner with equal parts plate discipline, opportunism and sacrifice.

Denard Span reached base and stole second. Anthony Rendon moved him to third with a here-take-my-out grounder to second. And LaRoche drove home the game-winner.

“That was textbook,” LaRoche said. “We’ve done that a few times and got that guy on third and just haven’t got him in. We’ve taken care of the first couple parts of it. Nice to complete it there. To get a hit there, it’s just a bonus. It worked out. This is kind of a sleeper team. You lay down on them, you can look up in the ninth and you’ll be losing. It’s nice to come back there.”

Hours after Bryce Harper underwent thumb surgery likely to sideline him until July, the Nationals came back to avoid a loss against a foe that entered 9-17. Nationals starter Gio Gonzalez struck out nine and allowed five hits in six innings. Three of those hits came in succession, with two outs in the third inning, a spasm that cost him the lead and, ultimately, a chance at a win. Craig Stammen and Tyler Clippard each tossed scoreless innings, which set up Rafael Soriano for his fifth save and allowed the Nationals’ offense a chance to chip away.

The Nationals left the bases loaded in the eighth after they tied the game, and Span led off the ninth inning. He drew a four-pitch walk against reliever Josh Fields. When Span reached first base, coach Tony Tarasco informed him Fields’s delivery to the plate took 1.4 seconds on average.

“This is a guy you can get,” Tarasco told him.

Span had the green light. In a spot that everyone in the stadium knew called for a steal, Span studied Fields, got a jump and swiped second base.

Rendon, a Houston native with the red-clad cheering section to prove it, worked a 3-1 count against Fields. In an advantageous spot, he remained content in performing a task. He broke his bat hitting a groundball to the right side, which pushed Span to third with one out for the meat of the order.

“He can handle the bat,” Williams said. “It wasn’t exactly what he wanted, but he was able to advance the guy to third. So that’s team baseball.”

Up came Jayson Werth, who had already homered and jolted three other baseballs. Werth cursed himself when he could not lift pitches out of the zone for sac flies, but he settled for a walk and left the inning to LaRoche.

“That’s really been my focus lately,” Werth said. “Get on base for Rochie.”

The Post Sports Live crew debates whether Bryce Harper's intense style of play attributed to his hand injury. (Post Sports Live/The Washington Post)

And why not? After his dismal 2013 season, during which he battled weight loss and a subsequent decrease in bat speed, LaRoche has rebounded to again serve as a lynchpin in the middle of the Nationals’ lineup. He entered Tuesday leading the Nationals with a .307 batting average and a .413 on-base percentage, spraying drives to every corner of the field.

“When he’s right and when he feels good, the ball goes in the middle of the diamond,” Williams said.

LaRoche has crushed the ball this month, especially to center field and right-center. Against Fields, he roped an inside fastball up the middle and into center field. Span trotted home with the run the Nationals needed, giving them a 4-3 lead.

“When I’m feeling pretty good, one, I’m taking some walks,” LaRoche said. “Two, I’m using the whole field.”

An inning prior, LaRoche had tied the score with a similar up-the-middle approach. With Werth on first after a single, Houston Manager Bo Porter summoned left-hander Raul Valdes to face Adam LaRoche. Last season, left-handers decimated LaRoche. This April, LaRoche has stung the ball against all pitchers.

Valdes slung an 87-mph fastball over the plate, and LaRoche launched it to left-center field. Center fielder Dexter Fowler sprinted to the gap. Werth bolted to second, took a couple more steps and watched the ball descend and Fowler count steps. Fowler leapt at the wall, and the ball squirted loose. Werth re-started his sprint, and he slid home just before the relay throw arrived to tie the score at 3.

“He’s a big piece of the puzzle here,” Werth said. “We’re a little banged up right now, so we’re going to have to pick up for the guys that aren’t on the club right now. We’re doing it.”

Werth sparked the Nationals in the first. Cosart leaped ahead of Werth in the count, 0-2, and tried to finish him off with a curveball. But Cosart hung it, and Werth nearly blasted out of the stadium. He launched the ball over the left field wall, over the left field seats and clanging off a metal Halliburton advertisement. In Texas, if you hit a baseball far enough, chances are it will meet a Halliburton sign.

The Nationals struck again in the third inning in wholly different fashion. Leading off the inning, Frandsen struck his elbow out at Cosart’s slow curve to give the Nationals a base runner. Werth used power; Frandsen employed guile and a sturdy elbow pad.

The next batter, Jose Lobaton, roped a double into the right field corner. Frandsen bolted from contact, and he circled the bases to give the Nationals a 2-0 lead. On April 18, Lobaton was hitting .171. Over the next 12 days, he has given the Nationals every bit as much offensive punch as Wilson Ramos could have. The double gave him 11 hits, four of them for extra bases, in 26 at-bats.

In the ninth, the Nationals would hold on for dear life after Soriano walked two batters. He rallied for his 22nd consecutive scoreless inning, dating back to last year. The Nationals lined up outside the dugout, and the slapping of hands echoed throughout an emptying ballpark.