PHILADELPHIA -- The starting pitching staff of the Philadelphia Phillies was being lauded heading into a weekend series with the Washington Nationals. Their starters had baseball’s lowest ERA entering Friday’s game.

It took the Nationals one inning to silence all talk, and their offense never stopped in a 9-1 drubbing of the Phillies at Citizens Bank Park.

Washington improved to 8-1 on the season and halted a three-game winning streak from the Phillies (5-6).

Phillies starter Jeremy Hellickson lasted just three innings after staking the Nationals to a 5-0 lead in the first inning. The righty had his ERA jump from 1.54 to 4.30, giving up six runs (five earned) and seven hits to go with a walk one and three strikeouts.

The Nationals outhit the Phillies, 16-4, and had a 9-0 lead in the top of the sixth when Bryce Harper sent a first-pitch offering from Brett Oberholtzer over the fence in right field. The two-run shot was Harper’s third hit of the night. Every Nationals starter registered a hit, including starting pitcher Joe Ross, who doubled in the first inning.

Ross was dominant on the mound, scattering three hits across 7 2/3 innings of work. Ross, 22, in his second season in Washington, struck out five Phillies while walking a pair. He was taken out in the eighth inning after a Freddy Galvis single.

Ryan Howard provided the only offense for the Phillies. The veteran first baseman squared up a Yusmeiro Petit fastball to lead off the ninth inning with a home run to right field, his second in as many days and fourth on the season, tying Joe DiMaggio for 81st place in MLB history with 361 career home runs.

The Nationals sent 10 batters to the plate in the first inning. Michael A. Taylor took Hellickson's second pitch of the game, an off-speed pitch over the heart of the plate, deep into the seats in left field.

A lineout followed by back-to-back hits from Bryce Harper and Ryan Zimmerman and a walk to Daniel Murphy that loaded the bases for the inning's crushing blow, a bases-clearing double to the left-center field gap by former Phillies outfielder Jayson Werth, who later scored on a Danny Espinosa single.

Ross had the luxury of batting before he even took the mound. The 6-foot-4, 225-pound right-hander had a double of his own in the first inning. Hellickson was at 45 pitches before Ross threw one.

The 5-0 deficit the Phillies faced before coming to the plate -- which grew to 6-0 before Hellickson's night was done -- was larger than the total number of runs they had scored in all but one game before Friday.

NOTES: Friday was Jackie Robinson Day around the majors, celebrating the day (April 15) that Robinson broke the color barrier in 1947. All players wore Robinson's No. 42 on the back of their respective jerseys. ... Entering Friday, Phillies starting pitchers, through their first two turns in the rotation, had posted a major-league-best 2.14 ERA (15 ER, 63 IP), the lowest mark by a Phillies starting staff through the first 10 games of a season since 1972 and sixth lowest since 1913... The Nationals entered Friday with the league's second-best starting pitcher's ERA (2.33) ... The Phillies used their third different leadoff hitter in 11 games, inserting Emmanuel Burriss into the leadoff spot on Friday night. ... Each team entered the weekend series having completed a series sweep on Thursday. The Nationals completed a four-game sweep of the Atlanta Braves. The Phillies topped the Padres, finishing a three-game set.