WASHINGTON — Brooks Conrad made quite a first impression, keeping the Atlanta Braves’ winning streak and pursuit of the NL East lead in tact.

Conrad hit a pinch-hit, go-ahead three-run homer in the seventh inning and the Braves beat the Washington Nationals 9-8 on Friday night for their season-high fifth straight victory.

“(Conrad) couldn’t have had a better debut with this organization, that’s for sure,” Braves manager Bobby Cox said. “He was a good asset and won us the game tonight, probably.”

Yunel Escobar drew a leadoff walk from Jesus Colome (1-1) and moved to second on Matt Diaz’s sacrifice. Colome walked Casey Kotchman on a 3-2 pitch with two outs before Conrad, a 29-year-old rookie whose contract was purchased from Triple-A Gwinnett to replace the injured Kelly Johnson, crushed a 1-0 fastball over the right-field fence for his first career homer.

Conrad, who had a six-game call-up with Oakland last year, got the milestone ball from teammate Jeff Francoeur, who retrieved it from the Washington bullpen.

“Huge thrill, obviously the best experience I’ve had in the big leagues,” Conrad said. “It was only 12 days last year. It just feels awesome to come up in a situation like that and contribute right away.”

Boone Logan (1-0) pitched 1 1/3 perfect innings of relief. Rafael Soriano worked the ninth for his eighth save in nine tries, despite yielding Cristian Guzman’s two-out, two-run double.

Chipper Jones, Diaz and Escobar drove in two runs apiece for the Braves, who remained two games behind first-place Philadelphia in the NL East.

“Had we not come in on our longest winning streak of the season, we might have been primed for a letdown,” Jones said. “But I think everybody is starting to feel like we got a good streak going and we don’t want it to end — (we) certainly don’t want it to end here.”

Adam Dunn hit his 21st homer, the 299th of his career, for the Nationals, who lost their fourth straight. Guzman had three RBIs.

“We can’t sit here and say we’re better than we are,” Dunn said. “We need to find a way to win these games.”

Nationals pitchers issued six walks from the seventh inning on, a failure that wasn’t lost on manager Manny Acta.

“It is disturbing because obviously those last nine outs have been very hard to get for us,” Acta said. “When you come in, you don’t help yourself by walking guys.”

Josh Willingham’s RBI single in the first gave Washington a 1-0 lead, but the Braves tied it in the second on a run-scoring single by Diaz.

The Nationals went up 3-1 in the second. Willie Harris doubled with one out and scored when starting pitcher Ross Detwiler shot a hard grounder off second baseman Martin Prado’s glove for his first career hit and RBI. Detwiler went to second on Nyjer Morgan’s groundout and scored on Nick Johnson’s single to center.

The Braves tied in it in the third on Jones’ RBI double and Escobar’s single to left.

Dunn homered off Kenshin Kawakami leading off the fourth for a 4-3 lead.

Atlanta tied it in the fourth when Prado singled with one out, moved to second on a wild pitch and scored on Jones’ single to left. Brian McCann singled, knocking Detwiler from the game, and Escobar greeted Tyler Clippard with a run-scoring double for a 5-4 lead.

Detwiler worked 3 1/3 innings, his shortest outing of the year, and remained winless in nine starts. He allowed five runs on 10 hits, walked two and struck out one.

Washington tied it at 5 in the fifth, taking advantage of Kawakami’s throwing error to score an unearned run and force the Japanese right-hander from the game. Kawakami hit Willingham with a pitch then threw wildly to second on Guzman’s swinging bunt, moving Willingham to third. Boone Logan relieved and yielded an RBI groundout to Josh Bard.

Kawakami, pitching for the first time since exiting a start on June 24 at Atlanta when he was hit in the neck by a liner off the bat of Joba Chamberlain, allowed five runs — four earned — on six hits in 4 1-3 innings. He walked three and struck out six.

After Conrad’s homer, Guzman’s sacrifice fly in the seventh made it 8-6. Atlanta loaded the bases against Ron Villone in the eighth before Julian Tavarez relieved and surrendered a run-forcing walk to Diaz.

NOTES: Johnson (right wrist tendinitis) was placed on the 15-day disabled list before the game. ... OF Nate McLouth returned to the Atlanta lineup after missing five games with a left hamstring strain and went 1 for 6. ... Morgan, acquired Tuesday in a trade from Pittsburgh, was 0 for 4 with a stolen base in his Nationals debut. ... Washington’s racing presidents mimicked Michael Jackson dance moves during their fourth-inning sprint, with winner Tom Jefferson doing a celebratory moonwalk.