The Cubs have seen Matt Garza at his best when he is mowing down hitters with a devastating slider and well-placed fastball.

And they have seen their former teammate at his worst when he has trouble making a routine throw to first base.

Now with the Brewers, Garza watched the Cubs challenge his weakness in the first inning of their 3-0 victory Saturday at Wrigley Field.

The Cubs seemed to unnerve Garza when the first two batters bunted. Emilio Bonifacio led off with a first-pitch bunt single and Chris Coghlan sacrificed him to second.

With two outs, Starlin Castro doubled off the wall in right-center field to drive in Bonifacio and Nate Schierholtz drew a walk before Welington Castillo scored him and Castro with a double into the left-field corner.

"Yeah, he has a problem throwing the ball," Castillo said. "But a couple of guys went straight at him and that worked a little bit for us."

Castillo said such gamesmanship is simply part of baseball.

"He knows that's coming because if you have something going on, you know other teams are going to try to get you … try to get on base," Castillo said.

The three-run first was all Cubs starter Edwin Jackson (3-3, 3.98 ERA) needed as he went seven strong innings, allowing just four hits and striking out 11.

"The first inning was a hiccup and it sucks," Garza (2-4, 4.83) said. "That has been what it has been like all year. I'm just going to keep grinding. It's going to come together sooner or later."

Cubs manager Rick Renteria wouldn't confirm the Cubs early strategy was to force Garza to field bunts.

"I don't want to get into that, but we tried to get on base by putting the ball in his general area," Renteria allowed.

Bonifacio knew precisely what that meant.

"If you put (the bunt) right at him, he is going to run to the base," Bonifacio said. "That's why I tried to put a really good bunt down (to force a throw)."

Garza allowed just four hits over seven innings while striking out seven and talked about how the two-out hits ruined his day.

"I left a fastball up to Castro. Welington then caught a slider that was up and that was it," Garza said. "After that, there was nothing else. It was pitches up early and that's what got me."

Meanwhile, Jackson was at his very best, even after allowing a one-out single to Jean Segura in the seventh inning. Renteria went to the mound and Jackson assured him he could handle his business.