MILWAUKEE -- Save for a first inning home run by Neil Walker, Tanner Roark was at the top of his game Friday night at Miller Park but Jimmy Nelson was just a little bit better.

Walker's home run proved to be the difference as Nelson threw seven scoreless innings and tied his career high with 11 strikeouts as the Milwaukee Brewers extended their winning streak to three games with a 1-0 victory over the Washington Nationals.

"Very rarely do you lose a game, 1-0," Nationals manager Dusty Baker said. "Especially with our team and especially in the first inning. Usually, it doesn't hold up."

Nelson (11-6), though, was at his best. He held Washington to three hits and three walks and though he stranded runners in scoring position in each of the first two innings, was only really challenged once -- in the third inning when the Nationals loaded the bases with one out.

Trea Turner drew a leadoff walk, stole second and then took third on a passed ball. After striking out Daniel Murphy, Nelson walked Wilmer Difo and plunked Ryan Zimmerman, but he got himself out of it by striking out Howie Kendrick and Jayson Werth.

"That was the only time we had him on the ropes," Baker said. We just couldn't come up with that hit.

"He had us swinging at a few high fastballs and a lot of breaking balls in the dirt. He was tough but we helped him by swinging at a lot of balls."

Nelson faced the minimum over his final four innings of work.

"He had his good stuff going tonight," said Nationals right fielder Jayson Werth, who went 0-for-3 with a pair of strikeouts. "These are big games for them. He was fired up. He's usually pretty good but tonight, he had a little something else in the tank. He was hitting spots, had his breaking stuff working and pitched well."

Roark matched Nelson pitch-for-pitch. He retired 11 in a row after Walker's early home run and found himself in trouble of his own in the fifth, as Milwaukee loaded the bases with nobody out.

But Roark caught a big break when Orlando Arcia chopped a 1-2 fastball right in front of home plate. Catcher Jose Lobaton picked it up, stepped on the plate to retire Domingo Santana and had plenty of time to get Arcia at first.

That still left runners at second and third, but Roark escaped by striking out Nelson and gave way after the sixth, having given up just the one run on five hits while striking out 10.

"Tanner was very good," Baker said.

The Nationals didn't fare much better against Milwaukee's bullpen.

Josh Hader needed 12 pitches to strike out the side in the eighth and Corey Knebel struck out two more in the ninth for his third save in as many games and 32nd of the season.

"Both of those guys came out with their plus-plus stuff," Brewers manager Craig Counsell said. "It was Corey's third day in a row and stuff-wise, it was one of the best innings for him. Hader really just reared back and threw. Twelve pitches, 11 strikes -- that's quite an inning."

The loss did little to impact the playoff picture in the National League East, which Washington leads by 15 games over Miami.

Milwaukee, meanwhile, kept pace with the NL Central-leading Chicago Cubs, who hold a 3 1/2-game lead atop the division. The Brewers closed within 1 1/2 games of Colorado for the second wild card.

NOTES: Milwaukee bolstered its roster for the stretch run, recalling RHP Brandon Woodruff, LHP Wei-Chang Wang, RHP Junior Guerra and OF Brett Phillips from Triple-A Colorado Springs. The Brewers also selected the contract of RHP Taylor Williams from Double-A Biloxi and activated C Andrew Susac and LHP Brent Suter from the 10-day disabled list. ... The Nationals brought RHPs Enny Romero and Ryan Madson off the 10-day disabled list and recalled RHPs Austin Adams and Erick Fredde from Triple-A Syracuse. C Raudy Read was called up to the big leagues for the first time after Washington selected his contract from Double-A Harrisburg. ... Brewers C Manny Pina underwent testing on his ailing right hip Friday and sat out a third consecutive game. ... The Nationals struck out 17 times Friday, tying their season high. ... Brewers OF Ryan Braun was ejected in the fourth inning for arguing balls and strikes with home plate umpire Mark Ripperger.