Stephen Strasburg delivers a pitch during his shutout of the Marlins on Wednesday at Nationals Park. The right-hander struck out eight and walked one, allowing just six hits while improving to 11-4. (John McDonnell/The Washington Post)

Perception always seems to consume reality when it comes to Stephen Strasburg. Injuries and the horde of stars around him sometimes combine to mask his ability, poke holes in his résumé and otherwise diminish what is and always has been a once-in-a-generation talent.

Wednesday’s 4-0 win over the Miami Marlins provided a reminder of exactly what the Washington Nationals have in their enigmatic right-hander, of what they missed when he was injured last October and of his evolution.

Strasburg did to the Marlins what the Nationals did to Miami’s push for a wild-card spot this week: He all but shut it down, throwing the second complete game of his career (both have been shutouts; the first came in August 2013). Strasburg (11-4) had recorded an out in the ninth inning only twice in his career before Wednesday. His ERA dropped to 2.90.

The Marlins came to the District with a chance to cut the Nationals’ division lead to single digits and stir doubt in the process. Instead, the Nationals outscored them 23-5 and sent them home 15 games back. The Nationals’ magic number to clinch the division title is 16, and these teams meet again Monday in Miami. That number could shrink fast.

On Wednesday, it shrunk because Strasburg delivered one of the best all-around games of his professional career. He allowed six hits and struck out eight while intentionally walking one. He also homered to right center and singled, results that came as a surprise to him given that he had not picked up a bat in more than a week, since two starts ago in San Diego.

“Oppo? Wow,” his catcher, Jose Lobaton, said after the game. “That was impressive. That was something special. As soon as I saw that, I was like, ‘This is going to be pretty good today.’ ”

Sometimes Strasburg accumulates strikeouts with the best of them. Entering Thursday, his 10.50 strikeouts-per-nine ranked third in the National League behind only Max Scherzer and Clayton Kershaw.

Other times, he pitches to contact. He added his cutter to help him do that last year but threw the pitch so often he believed it contributed to the torn pronator tendon in his throwing arm.

This year, Strasburg seems to have found a healthier balance. He has thrown less than half the sliders he threw last year. He has thrown more curveballs and change-ups than his career average and a lower percentage of fastballs.

“[I try to] throw a couple pitches early that produce quick outs instead of just being too heavy on the fastball,” Strasburg said. “I think across the league that’s what’s happening. “

On Wednesday, against a deep and powerful Miami lineup, Strasburg relied heavily on that change-up and his curveball to slice through the Marlins’ order. Through four innings, he threw just 42 pitches. Most pitchers target 15 per inning.

Strasburg ran into more serious trouble in the fifth when J.T. Realmuto grounded a ball up the third base line, just out of reach of Anthony Rendon. Realmuto appeared to slow down rounding second, which seemed to lull left fielder Howie Kendrick into thinking he had time to send the ball back in, but Realmuto broke for third and ended up with a leadoff triple.

Needing strikeouts to keep the Marlins from scoring, Strasburg turned to his fastball to get two of them. Derek Dietrich swung through a 96-mph fastball. So did A.J. Ellis, leaving Strasburg to get opposing starter Adam Conley to hit a weak flyball to end the inning.

The problem by that time, however, was that Conley had held the Nationals down, too — until Strasburg led off that fifth inning with a home run, his second of the season. He has hit more home runs this season (two) than Marlins leadoff man Dee Gordon (one).

So Strasburg took the mound with a lead in the sixth, when he, Lobaton and Manager Dusty Baker became more convinced that Wednesday was just his day. With one out in the sixth, Strasburg left a fastball up and over the middle of the plate to Giancarlo Stanton, who normally redirects mistakes like those over one fence or another. He hit this one 114 mph toward shortstop, where Trea Turner picked it, twirled and threw him out.

“That was a mistake. Not supposed to throw the ball right there,” Lobaton said after, with a smile. “. . . He should’ve hit that one far, but sometimes that happens.”

Many little things like that had to go right for Strasburg to do what he did Wednesday. Thanks to lots of early swings and plenty of weak contact, Strasburg finished the eighth inning at 87 pitches. He finished the ninth at 110, throwing more pitches in that inning than he had in any other. He bent but did not break.

Those who see Strasburg regularly know that he was not much of a pitch conservationist early in his career, which cost him chances to finish games. Even last season, Baker took him out of a no-hit bid because he had thrown too many pitches.

But this smarter Strasburg, the one who pitches exclusively from the stretch to save energy and minimize injury risk, is mastering the art of quick outs. On Wednesday, he provided a clinic on the subject to the announced crowd of 25,019.

His stated goal this season has been he wants to be healthy in October. If he is, the Nationals will have another starter able to take over a game, a rare talent on a roster that has so many of them that it sometimes obscures just how good Strasburg can be.