MILWAUKEE -- Alfonso Soriano squandered an opportunity when he grounded into a double play with the bases loaded. He didn't make the same mistake twice.
"He seems to do something in each win we have," Nationals manager Frank Robinson said.
Soriano went 3-for-4 to overcome a pair of bad plays. He made a baserunning error in the first and grounded into a double play with the bases loaded in the fourth.
All of that was forgotten when he hit his third career grand slam in his next at-bat in the sixth inning. Soriano said he wasn't thinking about the double play when he came up in the sixth.
"I take a couple of pitches and see the ball better and tried to make very good contact," he said.
After an intentional walk to Mike Vento put two on with two outs, Jorge De La Rosa (2-2) walked Nationals pitcher Tony Armas Jr. to load the bases.
De La Rosa was pulled for reliever Joe Winkelsas, and Soriano hit a 2-2 fastball into the Brewers' bullpen to give the Nationals a 6-0 lead.
"Sooner or later, he'll get you," Robinson said of Soriano. "You're dealing with fire."
That was more than enough for Armas (6-3), who allowed one unearned run and two hits in six innings. He retired the first nine Brewers -- three on strikeouts -- and 13 of the first 14.
"I'm very pleased with the way he pitched," Robinson said. "He threw strikes, he changed speeds, he got outs."
Milwaukee has now lost eight straight. The Brewers have been outscored 64-21 during the streak.
"We can come up with 95 different excuses and reasons why," manager Ned Yost said. "The bottom line is we're not winning. And that's it, you either get it done or you don't get it done and we're not getting it done. There's no excuse for that."
Geoff Jenkins is hitless in 15 straight at-bats and left with a mild concussion. Prince Fielder is also 0-for-15, and Carlos Lee is hitting .171 in his last 35 at-bats.
Washington could have scored even more against the hapless Brewers.
The Nationals had three hits in the first inning, but failed to score after Soriano got picked off trying to steal third and Royce Clayton stopped at third after Jose Vidro's double.
Soriano, now hitting .312 with 21 homers and 43 RBI, quickly made amends in his next at-bat in the third, hitting his first home run to deep center field to give Washington a 1-0 lead.
Soriano is second in the major leagues in home runs behind the Cardinals' Albert Pujols with 25, but Pujols is out indefinitely with a strained muscle on his right side.
Does Soriano want to win a home run title?
"I never think about it," he said. "I'd like to get the title (for) stolen bases, not homers, because I don't see myself like a home-run hitter. I like to run."
Meanwhile, there's nothing to like about Milwaukee's play right now.
The worst fielding team in baseball made three more errors on Sunday to increase its season total to 56, five more than second-place Cincinnati.
First, Fielder and Jenkins collided on a foul pop by Brendan Harris that neither reached in the top of the fourth, and while Jenkins played defense the rest of the inning, he was pulled immediately afterward. He is day to day.
De La Rosa walked Harris and Damian Jackson, then threw wide of Rickie Weeks on a sacrifice bunt by Brian Schneider. Weeks was given the error after the ball ricocheted off his glove allowing Harris to score.
Vento popped out to center, but De La Rosa mishandled a bunt by Armas for the second error in the fourth. That loaded the bases for Soriano, who grounded into a double play to end the inning.
The Brewers scored one in the sixth, one in the seventh and Gabe Gross hit a two-run homer in the eighth. But Weeks committed his major league-leading 20th error in the seventh that allowed Harris to score again.
"I'm fine, I'm fine, I just have to keep my head up," Weeks said. "You just have to roll with the punches, I guess."
Soriano's streak of home runs in consecutive series is now at nine, second-best in franchise history behind Vladimir Guerrero, who hit homers in 12 straight series in 2001. ... It was Soriano's second multihomer game of the season and the 13th of his career. ... Weeks has six errors more than anyone else in the league. ... The Nationals have won eight of their last 10 games facing a left-handed starter. ... Yost was ejected in the sixth for arguing balls and strikes.