PITTSBURGH -- Once again, the Pirates were set up to sweep their first series of the season after 12 fruitless attempts. And once again, they fell one game shy.

Pittsburgh dropped its series finale to the Nationals on Sunday afternoon at PNC Park, 6-2, as Bryse Wilson struggled to find his A-game.

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Wilson, who gave up five runs on seven hits and two walks in 4 1/3 innings, has produced a 7.04 ERA over his past three starts (12 runs in 15 1/3 innings). The third of those outings on Sunday featured a recurrence of a couple of themes from the first two: Home run damage and late-start struggles.

The right-hander allowed a homer to Luis García to lead off the second inning, but as many a pitcher will say, you can live with a solo home run. So when Alex Avila lifted another one with two outs in the fourth inning, Wilson just needed to regroup and get the final out of the inning.

It took longer than the Pirates hoped. Wilson allowed a double to Adrián Sanchez in the No. 8 spot and a single to pitcher Patrick Corbin, who completed seven innings vs. the Pirates. Lane Thomas made him pay as the lineup turned over, cranking a three-run homer to the right-field stands for the game’s decisive blow.

Against the White Sox on Aug. 31, Wilson gave up quick damage via a pair of solo home runs to Yasmani Grandal and José Abreu, then gave up back-to-back singles in the sixth that came around to score after he was pulled.

Then, against the Tigers on Monday at PNC Park, he kept the homers at bay and completed five strong innings. However, late-start runs cropped up in the sixth with a two-run double by Niko Goodrum and a sac fly by Miguel Cabrera, which put Detroit ahead at the time.

This time around was a bit different for Wilson, though, as he said he felt like he had more mechanical issues to work through. The right-hander said he had issues getting into his back leg and driving through his delivery, which affected most of his pitches.

“I think that led to velocity being down and the fastball -- four-seam and two-seam -- being a little bit flatter than usual,” Wilson said. “Yeah, I was searching for it pretty much all game, but it’s just one of those days where we couldn’t find it.”

The run prevention has seen peaks and valleys in Wilson’s short tenure with the Pirates since being acquired from the Braves for Richard Rodríguez at the Trade Deadline. And while his start on Sunday was one of his shakiest this season, both in results and in execution, manager Derek Shelton still sees the path of progress that the 23-year-old is on.

“I think we've seen definite growth in terms of ability to attack the strike zone and ability to execute pitches,” Shelton said. “I think today was just one of the days when he really didn't have it.”

Unfortunately for Pittsburgh, those struggles mean the team spoiled its 13th chance at a sweep this season, and it stands alone as the only club without one in 2021. The Pirates are not fazed by the possibility of going sweepless, as long as they keep creating those opportunities.

“Obviously, you want to get those wins against any team that you can,” said Kevin Newman, who tripled and made a strong defensive play in the first inning, “but we look at the positives and say that’s a series win. And, really, stringing those together is kind of the goal.”