Manny Machado beats Max Scherzer in deciding moment

There wasn't any theatrical, profanity-laced outburst on the mound tonight. Nationals manager Matt Williams remained in the dugout, allowing ace Max Scherzer to go mano a mano with one of the majors' elite hitters late in a one-run game with the season hanging by a thread.

This time, Scherzer lost the battle, surrendering a go-ahead two-run homer in the seventh to Orioles star Manny Machado as the Nationals fell 4-3.

Scherzer's bat helped the Nats rally in the fifth to take a 3-2 lead. Appearing to get stronger, Scherzer retired the Orioles in the sixth, whiffing Matt Wieters and Jonathan Schoop for his 10th and 11th strikeouts.

"My pitch count really wasn't indicative of how I felt," Scherzer said." I was low 100s after the sixth, and I still felt strong. I still felt good. I knew I could go out there and compete for a full inning."

Scherzer began the seventh at 104 pitches when J.J. Hardy ripped a double to left-center. But the intense right-hander fought back, fanning Jimmy Paredes for his 12th strikeout and then getting Gerrardo Parra on a sharp groundout to Clint Robinson.

That set the stage for the duel with Machado. Scherzer had not hurled more than 119 pitches in a game this season. He began Machado's at-bat having thrown 117 tonight.

Machado fell behind 1-2 and then Scherzer just missed a strikeout on a heater off the plate. On a 2-2 count, Scherzer reared back for his 122nd pitch of the night, firing a 98 mph fastball and Machado destroyed it. The colossal clout soared deep to left-center field for a game-changing homer.

"I'm not bringing anybody in in that situation to face Machado other than Max," Williams said emphatically on the decision to stick with Scherzer. "The ball he hit is (98) miles an hour. He's feeling good, making pitches. Had him two strikes. Threw him a fastball for strike, swing and miss. Slider down for swing and miss. And left one up. He's a good hitter. He's also a good pitcher. Just made a mistake."

Scherzer explained his approach against Machado after the devastating loss.

"I was just trying to be aggressive with him," Scherzer said. "I know in that spot in that situation in the game, I knew it was my last hitter, so I was just letting everything eat. I found a way to get to a 1-2 count. I was just trying to absolutely let it fly and let it ride to the top of the zone. That's where I usually get a lot of swings and misses. When I challenged him with my best, he beat me. I've got to tip my hat to him. He put a great swing on it. Sometimes you get beat. Tonight's one of those nights."

Machado enjoyed his bomb, taking plenty of time gazing at the ball as it sailed toward the Red Porch at Nationals Park. On his next trip to the plate in the ninth, closer Jonathan Papelbon sent a fastball darting at Machado. Both benches cleared and Papelbon was ejected.

Meanwhile, Scherzer said he didn't even see Machado's home run celebration.

"I'm sure he was pumped," Scherzer said. "Hey, I'm pumped out on the mound, trying to come after you. He hit it. I really don't care."

For the second straight night, the Mets tried to help the Nats get back in the race by losing to the Braves. But the Nats failed to capitalize and the Mets' magic number is down to five to win the National League East.