Stephen Strasburg delivers against the Giants during the sixth inning. He struck out seven to bring his season total to 173. (Jeff Chiu/ASSOCIATED PRESS)

Wednesday afternoon, under a cloudless blue sky at AT&T Park, Stephen Strasburg offered one of the final impressions of his season, a show to appreciate and a break from the cacophony surrounding his impending shutdown. The performance — batters flailing at change-ups, falling out of the box against curveballs — encapsulated all of what makes Strasburg who he is, a figure worth protecting and begging to see more of.

Even as Strasburg dominated the San Francisco Giants for six innings, the Washington Nationals6-4 win illustrated a crucial tenet of their past success and future hopes: They are so much more than Strasburg. The Nationals won the series and closed their season-changing, 10-game trip with an 8-2 record. Their lineup knocked out Tim Lincecum after four innings, and after a harrowing finish they pushed the best record in the majors to 73-45.

The Nationals have gone 41-23 away from Nationals Park, where they will return Friday with Ian Desmond expected to be in the lineup at shortstop after missing 25 games. They have a better record on the road than any team except for the Cincinnati Reds does playing at home.

“Good teams play just as well on the road as they do at home,” Manager Davey Johnson said. “And we’re a good team.”

Strasburg allowed two runs and struck out seven in six innings, pushing his season total to 173 strikeouts, which led the league until the New York Mets’ R.A. Dickey reached 175 Wednesday night. He walked four batters, two of them coming to lead off the second, the ragged inning in which he yielded his only two runs. He made his other frames look easy, throwing 100 pitches total. He may have five starts remaining, perhaps more and perhaps fewer. His innings count for the year is 1391 / 3, a number he has pushed out of his mind.

“It’s out of my control,” Strasburg said. “I’m just doing everything I can to help this team win games and it’s all going to take care of itself in the end.”

Wednesday, the Nationals could have won with a lesser pitcher on the mound. Steve Lombardozzi swatted four hits, Danny Espinosa continued his second-half rampage with a booming two-run homer and Jayson Werth drove in three runs. All told, the team lashed 12 hits.

The Nationals tacked on two runs against the Giants’ bullpen, and they needed them after a scary ninth. With two outs in the ninth and a runner on second, closer Tyler Clippard induced a mile-high pop-up from Pablo Sandoval. Adam LaRoche settled under the ball, but the wind toyed with it in the bright sky.

“I got to be totally honest,” LaRoche said. “As confident as I am in my defense, if I got that ball 10 times in those circumstances — not a cloud in the sky, the wind blowing, the ball hit as high as it was — I may catch it about four or five. It was about halfway down. I gave myself a 50-50 chance. I was like, ‘I’m not in a good spot right here.’ ”

The ball grazed LaRoche’s mitt and bounced in the dirt. The game was over, and then it wasn’t. One run scored. Buster Posey, perhaps the hottest hitter in the league, strode to the plate.

“I wasn’t too worried about it, honestly,” Clippard said. “I was just like ‘Okay, let’s get this next guy.’ I moved on real fast.”

Posey, the tying run, worked the count to 2-1. Clippard tried to spot a fastball low and outside, and instead it ran in toward his hands. Posey whiffed. Clippard tried the same pitch again, and the same thing happened — the ball trailed back inside and high, and Posey foul-tipped it. The ball burrowed into Kurt Suzuki’s mitt. The Nationals were going home.

“We’ve got a little over a month and a half left,” Clippard said. “We’re playing good, we’re feeling good, but baseball’s a funny game. We don’t want to take anything for granted, but this was definitely an important road trip for us.”

Strasburg has helped lift the Nationals to their lofty status, but they are not in first place because of any single player. Their offense made certain a sparkling pitching matchup, Strasburg vs. Lincecum, a two-time Cy Young winner, fizzled early. The Nationals loaded the bases with two outs in the first inning, and Werth dumped a two-run single into left field to give the Nationals an instant lead.

The Giants stormed back, mounting their only rally in the second inning. Strasburg walked both Posey and Hunter Pence to lead off, and Brandon Belt loaded the bases with a single to right field. Strasburg struck out Gregor Blanco, but Brandon Crawford rifled a single to right, tying the score at 2.

“It was tough,” Strasburg said. “Sometimes that’ll happen. I think the worst pitch was three change-ups in a row to Crawford. That’s not the way I want to pitch guys.

He snapped into a groove. In his final four innings, Strasburg did not allow a runner past first base. He did not allow an extra base hit all game — the league is slugging .343 against him. He displayed all of his familiar traits. He struck out Pence in one at-bat with a 94-mph fastball that darted in on his hands. In another at-bat Pence nearly fell over backward taking a curve that curled in the zone for a strike.

“Once I told myself to just trust it and just let it happen, all my pitches started to come back and I started having a much better feel,” Strasburg said.

The Nationals still had to retake the lead. In the third, LaRoche led off with a double off Linecum. With two outs, the inning fell to Espinosa. Lincecum threw a wan fastball over the plate’s heart, 91 mph and static. The ball crashed into the eighth row, perhaps 430 feet from home plate. Espinosa trotted around the bases, and the Nationals had grabbed a 4-2 lead.

The Nats will fly home having put a hammerlock on their playoff chances, even with a quarter of the season remaining. They will take Thursday off and then begin a six-game homestand. Deeper into the future, they know, they will lose Strasburg. They also know, for all his greatness, they can win without him.

“We got to keep pushing,” LaRoche said. “We’ve seen some major meltdowns in September. I don’t foresee that here, at all, with this group. We’ll just keep hammering, hammering, hammering. And see what happens.”