WASHINGTON -- Third baseman Manny Machado had three eventful at-bats in the fifth, seventh and ninth innings that presented a lot of fireworks in an Interleague showdown Wednesday.

He was called out on strikes in the fifth when he was not granted time, and then lined a two-run, go-ahead homer with two outs in the seventh off ace Max Scherzer as the Baltimore Orioles beat the Washington Nationals 4-3 on Wednesday to keep their slim playoff hopes alive.

"He beat me. He put a good swing on it," Scherzer said. "I knew it was last batter. I thought my fastball was my best pitch (but) unfortunately he put a good swing on it."

The 30th homer of the year by Machado was a scorching liner to center that came on a 2-2 pitch from Scherzer (12-12), who struck out 12 batters and gave up four runs in 6 2/3 innings.

"What a great at-bat," Orioles manager Buck Showalter said of the Machado homer.

Machado was then hit by a pitch in the ninth with two outs and none on by closer Jonathan Papelbon, who was then ejected from the game by home plate umpire Mark Ripperger. Benches cleared but there was no incidents and Felipe Rivero came in to get the final out in the top of the ninth.

"It's something you just don't do," Machado said of getting hit in the upper left arm, near his head. "Don't do it that way. I don't think it's part of the game" to throw a pitch near the head.

"There's no reason for it," Orioles starter Chris Tillman said of a pitch up and in to Machado.

Papelbon said he wasn't given a reason for why he was ejected. He also said he would not get into a "back and forth" of whether he tried to hit Machado or not.

"We have to keep our cool out there let the game play out," said Papelbon, who felt the crowd influenced the decision by the umpire to eject him. "If he thinks I hit him that is what he thinks."

The Orioles (75-76), now 3-2 against Washington this year, began the day five games back of the second wild card spot in the American League. The Nationals (78-73) started the night 6 1/2 games behind the first-place New York Mets in the National League East.

Orioles shortstop J.J. Hardy began the seventh with a double. After Scherzer retired the next two batters, Machado hit his homer two innings after he was irate after he struck out looking when he was not granted time by Ripperger.

Tillman (10-11) allowed three runs and six hits in six innings. Reliever Mychal Givens pitched two scoreless innings for the Orioles and Darren O'Day worked a perfect ninth for his second save in two days and fifth of the season.

"He pitched really well. He had to (in order) to match Scherzer," Showalter said of Tillman.

Orioles left fielder Steve Pearce had a two-run homer in the first and a double in the eighth.

Nationals third baseman Yunel Escobar had two hits against Baltimore, which leads the all-time series, 32-23. The Orioles are 17-6 in one-run games against Washington in the 10-year series.

Pearce hit a two-run homer in the first to give the Orioles a 2-0 lead. It was the 14th homer of the year for Pearce and the 26th homer allowed by Scherzer, who gave up 18 last year with the Detroit Tigers.

The Nationals scored in the bottom first when Escobar had an RBI single to drive in second baseman Anthony Rendon, who led off with a double against Tillman.

After Tillman gave up a walk to Harper in the first, he retired the next 12 batters before center fielder Michael A. Taylor drew a one-out walk in the fifth.

The next batter, catcher Wilson Ramos, doubled down the left-field line to score Taylor and tie it at 2. Rendon had a sacrifice fly later in the inning to make it 3-2, but the Nationals left the bases loaded after left fielder Jayson Werth grounded out to end the threat.

Scherzer was 1-3 in his previous nine starts and had given up 15 runs in his previous four starts at home.

"I felt really strong in the seventh. I want to have the ball in those situations," he said. But the ball he threw to Machado landed in the seats in center and with it the playoff chances of the Nationals are very slim.

NOTES: Nationals RHP Max Scherzer had his 243rd strikeout of the season -- a Nationals record -- when he set down Orioles 2B Jonathan Schoop in the fourth inning. The previous mark of 242 was set last year by RHP Stephen Strasburg. ... Orioles manager and former Yankees skipper Buck Showalter had fond memories of Yogi Berra, the Yankees Hall of Fame catcher who died Tuesday at age 90. "He always had time for me," said Showalter, the Yankees' manager from 1992 to 1995. "He was a special man. He was as good of a person as he was a player. He had such common sense. A sad day." Showalter noted that Berra once struck out just 12 times in a season -- in 1950 when he hit .322 with 28 homers in 597 at-bats. Washington manager Matt Williams said of Berra: "I think we lost a great ambassador to our game." ... Washington RHP Tanner Roark (4-6, 4.73 ERA) will face Baltimore rookie RHP Tyler Wilson (2-2, 3.72) on Thursday in the series finale. That is a makeup game after the teams were rained out Monday. ... Baltimore CF Adam Jones (back spasms) was out of the starting lineup again Wednesday. ... Orioles INF/OF Ryan Flaherty made his first start of the year in the outfield, in right.