WASHINGTON — Philadelphia's Sean O'Sullivan left Friday's start regretting a first-inning curveball that didn't get down and in enough to evade Bryce Harper's bat.
If only the Phillies could punish similar mistakes.
"It definitely didn't get where I wanted it to go," O'Sullivan said of the pitch.
Danny Espinosa also homered off O'Sullivan (0-1), who allowed four runs in five innings as the Phillies sank to their sixth straight loss. It's their longest slide since another six-game streak spanning June and July of last year.
The same starters squared off on Sunday in Philadelphia in the game that began the slide, though neither figured in the Nationals' 4-3, 10-inning victory.
Odubel Herrera had two hits Friday, including a triple, and scored Philadelphia's first run, and Ryan Howard's ninth-inning single drove in the other.
The Phillies have scored only 26 runs in 11 games while batting .154 on the season (12 for 78) with runners in scoring position. They failed in both such chances against Scherzer (1-1) in this one, and went 1 for 4 overall.
"We need that hit the first inning or second inning that kind of just, you know, makes us breathe a little bit," said Jeff Francoeur, who went 1 for 3 before being removed in a double-switch.
Scherzer scattered four hits and one run, and struck out nine in his third start since he signed a seven-year, $210 million contract in January. The right-hander has allowed two earned runs in 21 2-3 innings.
He allowed two first-inning singles, but got Cody Asche to hit into an inning-ending groundout and took control from there. He struck out at least one batter in each of the next six innings.
"He had pretty good stuff," Phillies manager Ryne Sandberg said. "He mixes it real well, and he's so herky jerky out there ... it looks like he's hard to zone in on."
O'Sullivan allowed four runs and five hits, settling down after a rocky first. But the damage was done.
After a single, a hit batter and one fly ball out, the righty hung a 1-2 curveball to Harper, who mashed the pitch over the center-field wall for his third home run of the season.
Espinoza added his solo shot in the fourth, and the Nationals scored three more in the seventh off the bullpen.
O'Sullivan was also frustrated with himself for not getting his fifth-inning bunt down. Instead, Zimmerman made a diving catch in foul territory for the second out with a runner on first.
"That was unacceptable," he said. "Unacceptable."
The Phillies have yielded 15 home runs so far, including two Friday. They entered Friday leading the majors in that category.
Phillies OF Domonic Brown (left achilles tendinitis) is expected to continue his rehab with Triple-A Lehigh Valley in its weekend series in Buffalo after going 5 for 17 in six games with Class A Clearwater. Brown was not in Friday's starting lineup for Lehigh Valley after playing in Clearwater on Thursday.