Anthony Rendon cracks a two-run double in the fourth inning. (Thomas B. Shea/Getty Images)

They stood behind the Washington Nationals’ dugout, wearing red T-shirts and white jerseys with No. 6 on the back, making more noise than the rest of Minute Maid Park combined. Others watched from the left field corner; two of them unfurled a sign that read, “GO ANTHONY #6!!” They hollered for Anthony Rendon, their friend, or their cousin, or, in the case of Rene Rendon, the pool player who organized the raucous cluster, their son.

They had been boisterous even before the Nationals’ 7-0 romp over the Houston Astros, which gave Jordan Zimmermann his 45th career win, making him the team’s all-time winningest pitcher. They had cheered even before Rendon showed off the swing they had all seen before — hitting pinecones as kid in the Southwest section of Houston, honing his stroke during days at Lamar High with Astro-turned-coach Willie Ansley, winning national awards at Rice.

To end his first trip home as a major leaguer, Rendon went 4 for 5 with a home run, two doubles and three RBI. Along with Zimmermann’s 61 / 3 scoreless innings, Rendon lifted the Nationals’ depleted-yet-destructive lineup to a two-game series sweep. A couple hundred family members, friends and former teammates watched from the stands, too many for Rendon to provide an exact number.

“Rice education doesn’t let me count that high,” he said, grinning.

Rendon, 23, gave them a performance representative of the damage his elegant swing can do. He’s not one type of hitter; he’s every type of hitter. His piston-quick wrists allow him to let a pitch travel longer than most hitters. Manager Matt Williams sometimes assumes Rendon is taking a pitch, only for him to swing and whack a line drive somewhere.

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)

Tuesday night, nerves prevented Rendon from his best showing. He went 1 for 5 with two strikeouts, his first multiple-strikeout game of the season.

“I was swinging a little hard,” Rendon said. “I was trying to hit the ball too hard. I just slowed things down. More is less. Less is more.”

Wednesday night, he showed up relaxed. He had spent all day at his parents’ house with family, some of which he hadn’t seen in years. At the park, his aunt brought a sign. He heard teammates from Rice shout their nickname for him, a Spanish word he declined to reveal. “It’s definitely an inside joke,” he said.

In his first at-bat, Rendon drilled Brett Oberholtzer’s 3-2 fastball off the right-field fence. In his second, he lined a 1-2 knuckle curve to right for a single. In his third, he pulled a 1-2 fastball into the left-field corner for a two-run double. Finally, he blasted Paul Clemens’s 2-1 change-up over the wall in right field.

“He can hit the ball line to line,” Williams said. “Tonight, he proved it again. It’s hard to do. If you’re going to hit the ball the other way like he does, it’s hard to pull it. He stays back and sees the ball as long as he can, and he’s got a really short swing.”

When they dust settled, Rendon had raised his average to .316, hit his fourth home run and pushed his team-leading RBI total to 20. Through his team’s attrition and his own excellence, Rendon, the sixth pick of the 2011 draft, has become one of the most pivotal Nationals in his first full season.

His defense, both in quality and versatility, has been invaluable, too. When Ryan Zimmerman broke his thumb, he shifted from second to third, the position he played at Rice, and opened the way for Danny Espinosa to play second. Wednesday, he added to his highlight cannon with a diving stop to his left.

In one month, enough time passed and injuries happened for the Nationals’ opening day lineup to morph into the post-nuclear lineup they employed Wednesday night. Scroll down the latest order, and it took just five spots to hit Tyler Moore, the first player who started the year in Class AAA Syracuse. Two others loomed below. Only two of the Nationals’ top six hitters on opening day remained.

Decimated lineup or not, the Nationals’ offense produced. It happened against the Astros, who are a still kind of special mess. But still, without Zimmerman, Wilson Ramos, Bryce Harper and Adam LaRoche, who had the night off to rest a balky quad, the Nationals mashed 13 hits, including Espinosa’s third homer, and committed no errors.

Zimmermann would have been good enough for any lineup to win. He scattered seven hits, all singles, struck out seven, walked one and barely broke a sweat. Thought he didn’t have his best stuff, it was a vintage performance fit for a milestone night. With the 45th win of his career, Zimmermann passed Livan Hernandez for most since baseball returned to D.C. in 2005.

“It means a lot,” Zimmermann said. “I can actually ride Livo, now. It feels good to pass up a good friend. It means I’m doing my job. Wins aren’t everything as a starting pitcher, as long as they team wins. But to get that many means I’m doing something right.”

Denard Span sparked the Nationals’ with a triple that turned into a Little League-style homer after right fielder George Springer’s error. Kevin Frandsen, a jolt of energy all year, started another rally in the third with a first-to-third sprint.

Rendon would break the game open with his two-run double, and the segment of Minute Maid Park that had come to see him erupted. His night nearly turned from preposterous into a dream - in his last at-bat, he launched a ball to the warning track in left. He would have to settle for merely his best game as a big leaguer in the place he grew up.

“It was great,” Williams said. “Wasn’t it?”