Based on how he and his teammates are doing, it's looking more and more as if they might reach the actual postseason.
The Cubs, holding the lead for the second NL wild-card spot, completed their first undefeated homestand of at least seven games since 2008. They began this stay at Wrigley Field by sweeping four from San Francisco, then took three from the Brewers.
''That's the mindset that we need to have, is we're playing in the playoffs every day,'' Schwarber said.
Schwarber later connected in the seventh and has two multihomer performances in 31 games of his first season in the majors. Fellow rookie Kris Bryant extended his hitting streak to 10 games and Chris Denorfia later added the Cubs' fifth homer of the day.
Lester (8-8) struck out 10 in six innings. He gave up two runs and seven hits.
''He had to battle through some moments but he was really, really good,'' Chicago manager Joe Maddon said.
Lester didn't go at least seven innings for the first time since June 25 and his struggle with holding baserunners was exploited. He allowed five stolen bases - including four in the third.
The left-hander was charged with an error when his pickoff throw in the third sailed past Rizzo at first base, letting Jean Segura advance. Segura stole third with Lester holding the ball and scored on Ryan Braun infield's single.
Lester stressed he would continue to work on his throws to first, and that he wouldn't give up on it with two months left in the season.
''Just got to do a better job,'' Lester said. ''Tried to pick over today. Felt good about it, wasn't a bad, terrible throw.''
With one out, Fowler was credited with a two-run homer after his drive to right was originally called a double after it bounced off the wall behind the overhanging basket. Schwarber then followed with his seventh homer.
Knebel replaced Cravy, and allowed Rizzo's 22nd home run of the season to give the Cubs three homers in an inning for the first time since Aug. 29, 2011, at San Francisco.
Braun had three hits, but Milwaukee couldn't avoid the sweep by the streaking Cubs. That said, Brewers manager Craig Counsell didn't think visiting Chicago at this time was a factor.
''No, we got our butts kicked. I mean, it's pretty simple,'' Counsell said. ''The Cubs are playing well, but we got our butts kicked.''
The Cubs are happy with what they're doing but aren't satisfied.
''The vibe's good,'' Maddon said. ''We've got to keep it going.''
During the national anthem, the U.S. Navy's Blue Angels flew over Wrigley Field. They are in Chicago for the local Air & Water Show, which takes place this weekend. Jets flew over and near Wrigley Field numerous times during the early parts of the game.
Lester recorded his fourth double-digit strikeout game of the season and 24th of his career. He's the first lefty in Cubs history with four double-digit strikeout games in a year.
Brewers: RHP Johnny Hellweg, a top pitching prospect, continues to progress as he returns from Tommy John surgery. Hellweg hit 98 mph in his last start Tuesday at Class A Brevard County.
Cubs: RHP Kyle Hendricks (6-5, 3.73) faces White Sox RHP Jeff Samardzija (8-7, 4.62) on Friday at U.S. Cellular Field. Samardzija spent parts of seven seasons with the Cubs before being traded to Oakland in July 2014.