MILWAUKEE -- The Milwaukee Brewers knew there would be some growing pains when they inserted young right-hander Jimmy Nelson into their starting rotation this season, so his up-and-down start isn't surprising.

But for Nelson, an outing like Saturday, when he gave up seven runs in five-plus innings of a 7-2 loss to the Washington Nationals, is not part of his plan.

"It is just unacceptable," Nelson said. "I just have to be more consistent. I have to be better. Not just next time out, but every one of my outings.

"That's the frustrating part to me right now. I'm working hard to get that consistency, but the last couple of weeks it has been up and down. That's the most frustrating thing right now. I'm just going to keep working."

Nationals right fielder Bryce Harper was especially tough on Nelson, singling three times and driving in two runs. He also drew a key walk in the fourth that set the stage for catcher Wilson Ramos' two-run homer, which broke open a one-run game.

Nelson had made quick work of the first two Washington batters and was ahead 1-2 to Harper, who worked the count full and laid off a close curveball to draw the walk. That brought up Ramos, who took one pitch before smacking a fastball to right to make it 5-2.

The Nationals scored one more run in the inning and Nelson put the first two batters on in the sixth, ending his day.

"He just never really got into a rhythm," Brewers manager Craig Counsell said. "I thought he made some really good pitches in the first inning. They hit some good pitches, I thought.

"I think that at-bat to Harper with two outs, I thought he made some good pitches but couldn't get him to bite, then he made a mistake to Ramos (for the home run)."

Nelson fell behind 1-0 in the first inning on an RBI single by Harper, but the Milwaukee offense came through in the second, putting two on the board when shortstop Jean Segura beat out an an RBI single to score first baseman Adam Lind. Segura scored on an RBI double by second baseman Scooter Gennett, who had two hits in the game.

Third baseman Yunel Escobar put Washington back out in front with a two-run homer in the third.

"The singles with guys in scoring position were huge," Washington manager Matt Williams said. "You're going to hit a homer every once and a while, to be able to put those back-to-back-to-back hits together is important."

Milwaukee missed a chance to tie or take the lead in the bottom of the inning when Segura was held up at third on Gennett's second double of the day. Nelson (3-7) struck out to end the inning and the Nationals took control in the fifth.

"You have a choice there to challenge the best (relay) guy in the league with two outs and the pitcher hitting," Counsell said. "You're also not going to just run into an out. It's always easier after you see what happens."

Washington right-hander Joe Ross (1-1) secured his first major league victory, going eight innings and getting eight strikeouts, including three against right fielder Ryan Braun and two against center fielder Carlos Gomez.

"I don't try to nitpick around the zone," Ross said. "I go after hitters and that kind of eliminates walks. And when I do get to the three-ball count, the 3-2 count, I try to really focus in on making a good pitch for hopefully a strikeout or a ground ball or whatever it is."

Ross gave up seven of Milwaukee's eight hits, but the Brewers were just 1-for-4 with runners in scoring position and stranded seven.

NOTES: Washington RHP Stephen Strasburg reported no issues after throwing 60 pitches during a live batting practice session Friday and could begin a rehab assignment sometime in the next week. Strasburg has been on the disabled list since May 30 because of neck tightness. ... RHP Doug Fister returned to Washington on Saturday after throwing six shutout innings in a reha