Chris Davis finished a perfect 4-for-4 with two homers and three RBI to offset Ryan Zimmerman's first career three-home run game, as the Orioles utilized a six-run seventh inning to outlast the Nationals, 9-6, in the first of a two-game interleague set at Camden Yards.
Nick Markakis added a solo homer and two RBI and Steve Pearce contributed a two-run shot as part of the game-changing seventh inning for the Orioles. Manny Machado and Ryan Flaherty also drove in one run in the victory.
Baltimore reliever Steve Johnson (1-1) earned the win after replacing starter Chris Tillman in the fifth with the Orioles trailing 6-2. Tillman lasted 4 2/3 innings, allowing six runs on eight hits, including four homers and all three of Zimmerman's shots.
"I thought Stevie's (Pearce) home run kind of brought us back," Orioles manager Buck Showalter said. "But probably the key outing was Johnson. That's going to be over looked."
Zimmerman homered in his first three at-bats and finished with four RBI. He became the second MLB player on Wednesday to go deep three times, joining Chicago Cubs catcher Dioner Navarro, who had three home runs in a 9-3 victory over the White Sox.
Washington starter Jordan Zimmermann (8-3), who was looking to become the MLB's first nine-game winner of the season, was charged with a season-high seven runs and 10 hits over six-plus innings to absorb the loss.
Roger Bernadina hit a solo homer and Denard Span drove in the other Washington run. The clubs split a pair of games in D.C. over the previous two days.
Baltimore ended Zimmermann's night in the bottom of the seventh. Trailing 6-3, the O's exploded for six runs thanks to five consecutive hits allowed by Zimmermann and reliever Tyler Clippard.
Flaherty smacked a leadoff single and Pearce came through with a two-run homer, making it 6-5. Nate McLouth then reached on an infield single before Machado plated him with an RBI double to left to tie the game at 6-6. That would be the last batter for Zimmermann.
Clippard entered the game looking to stop the bleeding, but he too ran into immediate trouble. Markakis hit a run-scoring single up the middle to give the O's a 7-6 lead.
Clippard forced Adam Jones to fly out to deep center, but Markakis alertly tagged up from second on the play. Davis rounded out the Baltimore rally with a punishing blast to center, his second of the game, which not only expanded Baltimore's lead to 9-6, but brought the home crowd to its feet.
"We always have a chance," Johnson said. "That's what's so great about this team. We always have a chance to come back."
Fittingly, Zimmerman opened up the scoring in the first, launching a two-out, solo shot to left-center to give the Nationals a 1-0 lead.
The Orioles tied the game at 1-1 in the second on Flaherty's RBI double down the right-field line, scoring Davis.
Washington stayed hot in the fourth with back-to-back homers. Bernadina opened the frame with a blast past the right-field foul pole and Zimmerman followed with his second homer, crushing Tillman's high fastball to dead-center for a 3-1 Nationals lead.
Not to be outdone, Davis added his first homer in the home half, a solo bomb to center, closing the hosts' deficit to 3-2.
The Nationals continued to attack Tillman in the fifth and eventually forced the righty out of the game.
Danny Espinosa, playing for the first time since May 22 after the team announced he had a broken bone in his wrist, reached on J.J. Hardy's throwing error at short and Span brought him home with a double to make it 5-2.
Zimmerman again figured out Tillman two batters later, smacking an opposite field homer to right for his third of the game, giving the Nats a 6-2 advantage.
Markakis joined in on the home run derby in the sixth by opening the frame with a homer to right-center, cutting the Orioles' deficit in half, 6-3.
Zimmerman headed into his fourth at-bat in the seventh having gone 3-for-3 with three homers and four RBI, but was fanned by Johnson.
Jim Johnson earned his 16th save of the season with a perfect ninth.
Zimmerman joined Adam Dunn (July 7, 2010) and Alfonso Soriano (April 21, 2006) as the only Nationals to hit three homers in one game ... The Orioles have won eight of the last 10 meetings at home in the series ... It was the first time since April 21 that Zimmermann didn't last past seven innings. He also entered the game allowing 3 runs or less in 15 consecutive starts overall -- which was good for the longest such streak in the majors ... The last time two players homered three times in one day came on Oct. 30 of last season by Dan Johnson of the White Sox and Evan Longoria of the Tampa Bay Rays.