Milwaukee Brewers' Francisco Rodriguez reacts after getting his third save of the season against the Pittsburgh Pirates during the ninth inning of a baseball game on Friday, April 11, 2014, in Milwaukee. The Brewers defeated the Pirates 4-2.

MILWAUKEE — Francisco Liriano had seven strikeouts and two big mistakes for the Pittsburgh Pirates.

The margin of error is slim when facing a streaking team like the Milwaukee Brewers.

Liriano befuddled the Brewers with his slider before giving up a two-run homer to Aramis Ramirez in the fourth that helped Milwaukee extend its winning streak to seven with a 4-2 victory Friday night over Pittsburgh.

The Brewers added two more runs in the fifth on a solo shot by Mark Reynolds and a two-out single from Carlos Gomez.

“I made two mistakes and you can't make those kinds of mistakes at this level,” said Liriano (0-2), who allowed four hits over six innings.

Pittsburgh star Andrew McCutchen had two steals but was lifted after lining out to end the eighth, when he told manager Clint Hurdle he may have hurt an ankle. The 2013 NL MVP appeared to be walking around in the clubhouse afterward without a limp.

“I had the trainer look at him and didn't think it was worth having him try to press on from there,” Hurdle said.

Ramirez kept up his torrid hitting with his drive to left on a 1-2 pitch, backing Wily Peralta's solid outing. At 8-2, the Brewers are off to their best start since opening with 13 wins in 1987.

“Everything's clicking. We'll continue to grind this thing out as best as we can, but we're doing a lot of good things,” manager Ron Roenicke said.

Ramirez's clutch hitting is at the top of the list. He is batting .727 (8 for 11) with runners in scoring position through the season's first 10 games.

“I would say that's part of job — I'm a cleanup hitter driving in runs, so I have to concentrate a little harder when I have guys in scoring position,” Ramirez said.

Milwaukee missed his bat for stretches of the 2013 season, when he was bothered by a left knee injury. Now, the Brewers have their cleanup hitter back, along with No. 3 hitter Ryan Braun, who returned from a 65-game suspension stemming from baseball's investigation of a Florida anti-aging clinic.

Peralta (1-0) allowed four hits in seven innings, but gave up a two-run homer to Neil Walker in the seventh.