MILWAUKEE -- Wily Peralta is having a hard time keeping batters off base. The Milwaukee Brewers are struggling to play decent defense.
That was a bad combination Thursday against the Chicago Cubs.
Matt Garza struck out 10 in seven innings and Dioner Navarro hit a three-run homer, sending the Cubs to a 7-2 victory over Milwaukee.
Peralta gave up seven runs, three earned, on eight hits and a walk while striking out two in five innings. He allowed the leadoff batter to reach base on singles in each of the first four innings, and three of those runners scored.
"We played really poorly behind him," Milwaukee manager Ron Roenicke said. "He didn't make pitches. He didn't pitch as well as he did last time but I was glad he came out and at least kept us in the ballgame and was able to give us five innings."
The Cubs broke the game open with four runs in the third, capped by Navarro's seventh homer. Milwaukee made a pair of errors and all the runs in the inning off Peralta were unearned.
"Nobody wants to make errors, but it's going to happen," Peralta said. "I still have to execute, make pitches and pick up my team, but I wasn't able to do that."
Left-handed hitters were batting .311 against Peralta (5-9) coming into the game, and Cubs manager Dale Sveum stacked his lineup with six lefties.
One of them was Navarro, who entered with just 85 at-bats.
"That three-run homer was huge," Sveum said. "To be able to get all those left-handers in the lineup and have everybody contribute was huge."
Garza (3-1) had his third consecutive strong outing. The right-hander allowed one run on eight hits and a walk while throwing 101 pitches.
Milwaukee's Juan Francisco homered for the third consecutive game, his ninth this year, but committed a costly error in the third that led to three unearned runs.
The Brewers dropped the final two games of the series and remained in last place in the NL Central.
"In order for us to get back in this or even get close, we certainly can't play this kind of ball," Roenicke said. "The starting pitching has definitely been better, the relief pitching has been great for a long time. We're getting more consistent offensively, but then we have some miscues like this, we don't bounce out of it and they really hurt us."
The third-inning errors were too much for Milwaukee to overcome. Starlin Castro led off with a single and stole second. One out later, Ryan Sweeney's liner to left went off the glove of Caleb Gindl for a two-base error, making it 3-0.
Anthony Rizzo struck out for the second out. Brian Bogusevic then hit a hard grounder to third, and Aramis Ramirez's throw to first was in time but went off Francisco's glove for the second error of the inning.
Navarro followed by hitting the first pitch from Peralta down the right-field line for a three-run homer to make it 6-0.
An error by second baseman Rickie Weeks in the fourth inning Wednesday night allowed two unearned runs to score in a 5-4 Cubs win over the Brewers.
NOTES: The game began with the roof open, but when rain threatened it was closed in the fifth inning. ... Sean Halton made his major league debut with a pinch-hit single in the fifth for Milwaukee. He was recalled from Triple-A Nashville before the game. ... Weeks extended his hitting streak to 11 games. Brewers SS Jean Segura ran his streak to 10 games.