Ian Desmond hits a two-run single in the third inning. (Thearon W. Henderson/Getty Images)

The night had promised so much to the fans who packed into the coolest ballpark in the majors. In the dugouts were the two hottest teams in the National League. On the mound stood an ace beginning to grasp the full extent of his powers. They love their San Francisco Giants at AT&T Park, and the year had only given them reason to boast, to raise another Anchor Steam, to add an extra layer when fog rolled off the bay and party all night.

At 9:28 p.m. local time, then, the Washington Nationals accomplished a rare feat. The aisles filled with black-and-orange clad fans. They headed for the closest exit, their backs turned to the best team in the National League, a team in the midst of receiving a 9-2 thrashing from the Nationals. Before the game, Michael Morse said fans here sing “Take On Me” with more fervor then they did at Nationals Park. When he came to bat in the seventh and took Aaron Barrett’s 0-2 fastball to the ribs, a good portion of would-be crooners had emptied out. 

The Nationals played the best game they can play, or at least something close to it. Stephen Strasburg dominated for six innings, striking out seven and walking none to continue the Nationals’ rotation’s incredible run. Shortstop Ian Desmond continued his recent power surge with three hits and a career-high five RBI. Denard Span ripped two doubles and a triple and scored two runs. 

The Nationals smashed eight extra-base hits and scored more runs at AT&T Park than any visitor all season. Their bullpen chipped in three one-run innings, and their defense played both flawless and spectacular. The Giants had won 14 of their previous 17 games and 42 of 63 overall. And the Nationals thumped them in every way the game allows. 

“It’s only one game,” center fielder Denard Span said. “We got a long series. We got three more games. We got [Madison] Bumgarner going tomorrow. That’s going to be a tough day. But we definitely felt good to come out and set the tone and have a good game against a good pitcher and a good team.”

The Nationals used the first leg of their four-game showdown with the Giants to declare their status as a full-fledged contender. The Nationals had won seven of their last nine, but they may have proved more in their eighth out of 10 than all the others combined. They entered with a 10-17 record this year against opponents with winning records. But they also played most of those games without Ryan Zimmerman, with whom they are now 12-5 this season. Over their past 10 games, eight of which Zimmerman has played, the Nationals have outscored opponents, 62-18.

Strasburg ran his record to 6-4, but he left after just 88 pitches in part because of minor stiffness in his oblique, which he started feeling in the third inning.  But both Strasburg and Manager Matt Williams said he could have — and would have — stayed in the game another inning if the Nationals had not opened up an eight-run lead with a five-run seventh.

“My back’s fine,” Strasburg said. "I put a little Hot Stuff on it. It seemed to help out a lot. I’m just trying to keep it as loose as possible.”

Giants starter Ryan Vogelsong entered with a 2.05 ERA in his previous eight starts, and the Nationals knocked him out with no outs in what became a five-run seventh inning. Strasburg continued an amazing run for Nationals starters: In the past seven games, they have 51 strikeouts against one walk. They are also the first starting rotation since 1914 to strike out 47 and walk none over a six-game span. 

“The biggest thing is, we’re just trying to go out there and keep it simple,” Strasburg said. “I think that’s kind of our identity. We’re going to go out there and pound the strike zone as a staff, let our defense do the work, keep it close, give our offense a chance to win the game.”

The Nationals’ defense made no errors and several strong plays. Zimmerman snared a sinking liner, his best play yet in left field. Kevin Frandsen, Anthony Rendon’s temporary replacement at third base, charged a swinging bunt, made a barehand grab and fired to first. Desmond ranged into the hole, leapt and fired a throw to first. Adam LaRoche converted both plays with slick scoops. 

“If we play well, then we've got a chance,” Williams said before the game. “If we don't, then against a team like this that’s playing so good, you're not going to win.”

In a moment that called for it, the Nationals played their best game of the season. It started with the game’s very first batter. Span smoked a double down the first base line, and he scored two batters later when Jayson Werth rocked a double to the left field wall.

The Nationals struck again in the second. With Wilson Ramos on first, Desmond obliterated a sinker that stayed up in the zone. The ball drilled the top of the fence just to the right of center field. Ramos scored from first, and Desmond cruised to third with a triple. He looked into the Nationals’ dugout and pumped his fist three times. 

In San Diego over the weekend, Desmond bashed two balls over the center field fence at one of baseball’s home run dungeons. In his first at-bat in San Francisco, Desmond drilled another ball to within inches of another tough location to leave the yard.

“Swing hard in case you hit it,” Desmond said.

Desmond has heated up in June, which follows a pattern. In 2012, Desmond hit .301/.333/.553 with five homers in June. In 2013, he hit .306/.355/.633 with nine homers. In the first 10 days of this June, he's slugging over .700. Desmond pointed out, “my wife's birthday is in June.”

“He's just staying through it,” Williams said Sunday. “His power has been to the center of the diamond. He’s got the ability to hit the ball anywhere he wants to. That just creates good swing path, when he's staying middle of the diamond. He's been working hard on that in batting practice, staying through the ball, hitting the ball the other way to the gap in BP. It just keeps him on the ball a little bit better.”

Span stoked the Nationals’ barrage in the seventh with another double. Frandsen’s single knocked out Vogelsong, and the Nationals hammered reliever George Kontos. Ramos’s ground-rule double and Desmond's two-run double, a grounder up the middle that scooted into the left-center gap, provided the most crushing blows. 

The only run Strasburg allowed came in the second, when Brandon Crawford followed Tyler Colvin’s double with an RBI single. Strasburg would allow only one base runner for the remainder of his outing, and he retired the final 11 batters he faced. As has become custom, Strasburg baffled hitters with his change-up. He also dotted his fastball with precision. Three of his strikeouts came with his fastball, three with the change-up and one with his curveball.

With the 88th and final pitch of his night, Strasburg struck out Buster Posey swinging at an 88-mph change-up. It has always been a good pitch. This season, it has become one of the most devastating offerings in all of baseball.

“I've just developed a better feel for it,” Strasburg said. “Being able to throw it for a strike when I want to, and being able to expand the zone with it. I think the biggest thing is being able to throw it for a strike. They can’t just sit there and eliminate, but it might be in there. They might be taking a strike.”

After Strasburg left, the only drama focused on whether Desmond could notch a cycle. He faced reliever Yusmeiro Petit, knowing he needed a homer. When he popped up to left field, Desmond spiked his bat on the way to first base.

“For the record, I probably shouldn't have slammed my bat,” Desmond said. “If Petit hears about this or sees this, I apologize. That was pretty bush league. But I was kind of caught up in the moment. You don't get that opportunity often.”

Late in the game, seagulls invaded from off the bay, circling above the right field fence. The birds may have grown accustomed to a packed ballpark and thunderous applause. The Giants had been the hottest team in the league. Monday night, the Nationals ripped the title from their hands.

“Tonight's over,” Williams said. “We go tomorrow. That’s all we can concentrate on is tomorrow. Against a really, really good left-handed pitcher. We won tonight, and that’s good, but we have to concentrate on playing a good game again tomorrow.”