WASHINGTON -- Both Stephen Strasburg and his catcher Yan Gomes were so locked in against the Marlins in the fourth inning on Wednesday night at Nationals Park that they didn’t even realize what they had accomplished. Strasburg had missed a spot on the first pitch of the inning, but it did not immediately register to him that the pitch still landed in the strike zone. Gomes threw the ball around the infield following the third out, like he normally does, but it did not occur to him that perhaps he should have kept the ball until he was back in the dugout.

Strasburg had just thrown the fifth immaculate inning of the 2019 season and the first of his career, a dominant frame as part of his best outing of the year. Strasburg rang up a season-high 14 strikeouts in 7 1/3 scoreless innings to lead the Nationals to a 3-1 victory over the Marlins.

With the win, Washington improved to a season-best three games over .500 (44-41). Since May 24, the Nats are 25-10, the best record in the Majors.

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Washington was carried by Strasburg, whose immaculate inning was the fourth in franchise history. Strasburg’s spotless frame -- when he punched out Garrett Cooper, Neil Walker and Starlin Castro on nine pitches -- came by mostly relying on his fastball. He threw four two-seamers, two of which were painted on the outside corner to freeze Cooper and Castro. Strasburg blew a 95-mph four-seam fastball past Walker to record the other strikeout.

Strasburg joined Max Scherzer (twice; June 5, 2018, vs. the Blue Jays, and May 14, 2017, vs. the Phillies) and Jordan Zimmermann (May 6, 2011, vs. the Marlins) as the only pitchers in team history to accomplish the feat. Boston's Chris Sale (twice), Toronto's Thomas Pannone and Milwaukee's Josh Hader are the other pitchers who have thrown an immaculate inning this season. And yet neither member of the Nats’ battery realized they had achieved an immaculate inning at the time.

“It kind of dawned on me a little later on,” Strasburg said.

“When things are rolling like that,” Gomes said, “you kind of just keep going batter to batter.”

During Strasburg’s most recent outings, he has appeared oddly sort of hittable. In his last eight starts leading up to Wednesday night, he had posted a 4.15 ERA, solid enough on the mound for the surging Nationals, but far from the dominant performances he is so routinely capable of producing.

But then there are outings where Strasburg seems as unhittable as he did Wednesday night. This was him at his best, spotting each of his four pitches with precision, his devastating changeup responsible for seven strikeouts with extra life on his fastball. Strasburg threw a 96.5-mph fastball during the sixth inning to Miguel Rojas, his fastest pitch of the season. He scattered five baserunners throughout the outing, allowing two hits, issuing two walks and hitting a batter, but limiting the Marlins to nothing else.

“I was able to execute from the get-go,” Strasburg said. “[I] was working on a couple things in the bullpen between starts. The changeup’s kind of gotten away from me. I just tried to get back to basics, and it seemed to be much better tonight.”

The Nats extended Strasburg into the eighth inning because this was his final start heading into the All-Star break. After a 2018 season defined and interrupted by hiccups and injuries, Strasburg just completed a full and healthy first half for the Nationals -- posting 18 starts, 10 wins, a 3.64 ERA, 138 strikeouts and 29 walks.

As Strasburg walked off the mound following his 14th strikeout of the night -- his best since he rang up 15 on May 27, 2017 -- on his 110th pitch, the crowd of 25,483 serenaded him with a standing ovation.

“He was moving the ball back and forth unbelievable,” Gomes said. “And then when he needed to make a pitch, it was right there. It was one of those things, he never gave in. He battled his tail off. It was quite hot out there, and he just made quick innings and did what he does.”