Nationals first baseman Adam LaRoche hits a two-run home run but it isn’t enough to beat the Dodgers. (Mark J. Terrill/Associated Press)

The Bryce Harper and Stephen Strasburg show would not hit town for another 24 hours, but Friday night offered enough to tide over the 44,807 at Dodger Stadium. Two surprise first-place teams, owners of the two best records in the National League, squared off. Prior to their biggest move this season, the Washington Nationals would receive their biggest test, against the reigning Cy Young award winner and the best player on the planet.

The Nationals acquitted themselves well enough to lose just barely to the Los Angeles Dodgers. Clayton Kershaw’s eight sparkling innings and too much Matt Kemp and Andre Ethier lifted the Dodgers to a 3-2 victory, handing the Nationals consecutive losses for the second time this year.

Ross Detwiler pitched well enough to win, allowing three runs over six innings on just five hits, striking out four. But the Nationals generated only three hits, including a two-run homer by Adam LaRoche, their offensive savior. The performance served as the latest reminder why the Nationals summoned Harper as both a salve and a run-scoring boost.

“Kind of discouraging,” Manager Davey Johnson said. “We had one more run than last night, but we still had three hits.”

The Nationals stayed in the game in the eighth inning because of a fantastic relay. With two outs and the Dodgers’ Tony Gwynn Jr. on first base, Juan Uribe rocketed a line drive to the right field corner. As Mark DeRosa picked up the ball with his bare hand, Gywnn sped around third. DeRosa ripped a throw to Espinosa, who pivoted and unleashed one of the best infield arms in baseball. The bullet of a one-hop throw skipped on the grass like a stone over water. Gywnn slid into home headfirst, but Flores blocked the plate with his right foot, and the inning ended.

Espinosa nearly tied it in the ninth, blasting a line down the right field line off Dodgers closer Kanley Jansen. It bounded off the top of the fence and into the seats hugging the foul pole. The park hushed. First base umpire Mark Carlson raised his hands, foul.

“I couldn’t really tell,” Espinosa said. “I knew the ball was hooking, but I couldn’t tell.”

A few Nationals in the dugout motioned for a replay review. If Manager Davey Johnson and the coaching asked for one, the umpires would have taken a look. The Nationals did not make the request. “It’s pretty easy to tell with a big, fat pole,” Johnson said. “That’s not a skinny pole. He was in perfect position.”

If the Nationals did ask for the review, it probably would not have mattered. The ball appeared to land maybe a half-foot to the right of the pole, but perhaps only after a fan interfered. Even after Espinosa watched the tape, he couldn’t draw a conclusion.

“Tough to tell,” Espinosa said. “It looked like a fan reached in front of the pole. It might have hit his hand and deflected back. I’m not 100 percent sure. It was close. No one could really tell.”

Against Detwiler, Kemp and Ethier went 4 for 5. The other seven Dodgers in the lineup went 1 for 15. Kemp and Ethier scored or drove in every Dodgers run, starting in the first inning.

Kershaw was supposed to square off against Strasburg, but in Washington rain last weekend pushed Strasburg’s start to tomorrow. The postponement gave Detwiler a stage. He entered Friday night with a 0.56 ERA after three starts, lowest in the majors, but still overlooked in the Nationals’ rotation. Thursday in San Diego, he sat on a clubhouse couch and listened to an MLB Network analyst extol the Nationals’ rotation and name every starter except Detwiler.

“Every time,” Detwiler said, smiling and shaking his head.

Detwiler began his start with two quick outs, including a whiff of leadoff hitter Dee Gordon. Then Kemp walked to the plate. If you want to know if baseball is alive and well, come to Dodger Stadium and listen to the roar as Kemp leaves the on-deck circle.

Detwiler got ahead of Kemp, 0-2, and lashed a pitch down and in for a single into left field. “I thought I made a good pitch,” Detwiler said.

But Detwiler still had to deal with Ethier. Detwiler threw a 1-0 curveball, trying sneak back into the count. Ethier smashed a home run to right field — “just good hitting,” Detwiler said. Detwiler had only allowed one earned run all season, but now he trailed, 2-0.

“He had a hard time getting curveball over early,” Johnson said. “They’re on fire. We didn’t make quality pitches. With a quality ball club, we can’t make mistakes. He threw a nothing curveball to Ethier on the inside half, he’s going to jump all over it.”

After the Nationals scored one run Thursday night, dropping their season scoring average to 3.63, Manager Davey Johnson made changes. He dropped Espinosa, batting .209 with a .308 on-base percentage, from second to sixth in the batting order. Johnson replaced Espinosa in the lineup with Steve Lombardozzi, whom he plans to make the regular third baseman with Ryan Zimmerman on the disabled list.

“The way we’re swinging the bats, jumbling the lineup up, shaking it up a little bit, it’s in order,” Johnson said.

Johnson may have chosen the wrong time for a shakeup, because Kershaw is an awfully difficult variable to factor into an experiment. The 2011 Cy Young winner entered Friday night with a 1.61 ERA. Until the sixth, Kershaw held the Nationals to two hits — one of them a double by Espinosa — and breezed through one inning with four pitches.

Jayson Werth broke Kershaw’s spell with a leadoff walk in the sixth. Kershaw quickly moved ahead of LaRoche with two strikes. LaRoche then blasted an 85-mph slider into the visitors’ bullpen in right field, one of the more unlikely home runs you will see. Kershaw had not allowed a home run all season. He had yielded only 14 homers to left-handed batters in his career. And he had given up only one home run in his career on an 0-2 pitch.

“Against a guy like that, it’s just straight grind mode,” LaRoche said. “You try to put the barrel on something and hope he makes a mistake. He’s one of those pitchers that’s effectively wild. He can throw one up under your chin or just as easily paint one down and away. Funky motion. Throws hard, looks harder than it is. When he’s on, shoot, good luck.”

In a blink, the Nationals had turned a moribund, 3-0 whitewash into a 3-2 nail-biter. In the final three innings, they produced just a single base runner, leaving them to wait until Saturday, to dream about Strasburg on the mound and Harper in left.