Wilson Ramos celebrates his solo home run with Ian Desmond during the sixth inning of the Nationals’ win over the Giants. (Alex Brandon/Associated Press)

A muggy weekend in early July does not avenge a few chilly October evenings, the memories irrelevant and the outcomes unrelated. Baseball seasons are too long, rosters too fluid and injuries too fickle to allow an autumn grudge to find satisfying resolution in the middle of summer.

But when the Washington Nationals beat the defending World Series champion San Francisco Giants, 3-1, on Sunday night to sweep a Fourth of July weekend series, they stepped forward. With wins in three games played in front of large holiday crowds and national television audiences, the Nationals moved 10 games over .500 for the first time all season — two weeks before they reached that mark on their way to 96 wins last season.

“We come into this series trying to beat these guys because, you know, last year, the postseason,” catcher Wilson Ramos said. “Now, we was playing really good against them. We have to keep playing like that.”

These Giants, losers of six straight, are not the same Giants that knocked the Nationals out of the 2014 playoffs. When asked, Nationals Manager Matt Williams would not acknowledge any added significance to this weekend’s series: This year is this year, not worth comparing to last year because there is no comparison. After all, these are not the same Nationals, either.

Officially more than halfway through the season, they are in first place in the National League East, though not comfortable yet. Like last year, good starting pitching decides their fate more often than not. But instead of relying on an experienced, stable lineup, this Nationals team must create with a scrappier, less seasoned one. As they have won 12 of their past 15 games, these Nationals have done that.

Even with injuries to Anthony Rendon, Jayson Werth and Ryan Zimmerman, the Nationals were able to win eight games in a row. Is the team overachieving with a depleted lineup? (Post Sports Live/The Washington Post)

Sunday’s win was built around a strong start, as were the 11 wins in 14 games before it. Nationals pitchers have allowed the fewest runs in baseball (28) during that time.

The last time Jordan Zimmermann faced the Giants, he pitched 8 2/3 scoreless innings and left with a lead in Game 2 of the National League Division Series. He owned a 2.79 ERA in eight starts against San Francisco entering Sunday night. More recently, Zimmermann had not allowed a run in 16 2/3 straight innings before Sunday and had not walked a batter in that time.

Both streaks ended Sunday, through Zimmermann shined again. Brandon Crawford hit a 3-0 fastball out of the park in the fourth to break the scoreless streak. Brandon Belt walked in the sixth, Zimmermann’s first walk in more than 20 innings. That was all the Giants got against him as Zimmermann threw 100 pitches over seven smooth innings. He struck out eight, walked one and scattered three hits to earn the win.

“Any time you sweep a team it’s special,” Zimmermann said. “Obviously, we’re going to win series. That’s our main goal. To take three from those guys and send ’em back home, it’s big for our ballclub.”

One of those newly minted Nationals regulars, Michael A. Taylor, supported him with an RBI single that drove home Ramos in the second. That was the only run the Nationals scored against Giants starter Ryan Vogelsong, who was ejected along with Giants Manager Bruce Bochy for arguing balls and strikes in the fifth. With a one-run lead and a man on first in the eighth, Taylor dove forward, parallel to the ground, glove fully extended to catch a sinking line drive from Angel Pagan against Matt Thornton.

Ramos has been quietly reliable this season. Traditionally vulnerable to injuries, he spent his offseason conditioning to prevent them and has stayed healthy throughout this season. His numbers are not prolific, but he is a consistent power threat in the middle of an injury-decimated Nationals order.

Against Giants reliever George Kontos on Sunday, Ramos hit a fastball a few rows over the out-of-town scoreboard in right-center field. He watched the ball fly and dropped his bat, which he had plenty of time to do — or so he thought.

The 30th U.S. president is putting on his running shoes and joining George Washington, Thomas Jefferson and the rest of the gang as the newest addition to the Washington Nationals' Presidents Race. Here are some facts about the former president and a peek at his sprinting skills. (Jason Aldag and Ashleigh Joplin/The Washington Post)

“As soon as I hit the ball, I felt on my bat the ball is gone. But I see the replay; it was just behind the wall,” he said. “Next time I need to hit it more hard and run a little bit more harder.”

It was his eighth home run of the season, 10th most among major league catchers. He drove in another run with a single in the eighth, his 38th, sixth most among those at his position. That single provided cushion for the Nationals’ bullpen, which turned to David Carpenter and Thornton for a scoreless eighth. Closer Drew Storen earned his 25th save in the ninth.

Three games in July do not make up for three in October, nor do they give any indication of what might happen this fall. But the Nationals swept the defending champions to move as far over .500 as they have been all season. Summer is no time for vengeance. This weekend, these 2015 Nationals settled for progress.