Garza finished with seven scoreless innings, allowing two baserunners and striking out 10 on 103 pitches.
The Phillies added a run in the ninth of Carlos Marmol when Ty Wigginton walked to score Pete Orr. The run came on three walks and an infield single.
Kyle Kendrick did not pitch poorly - he struck out seven, walked one, and allowed one home run in six innings - but his defense did little to back him up. In the second inning, Hunter Pence misplayed a ball in rightfield that ended up going for a double and set up a run.
In the third inning, Kendrick was charged with a throwing error that led to an unearned run.
The Cubs scored twice in the eighth inning off David Herndon.
The Phillies will look to split the series Monday against right-hander Jeff Samardzija. They then hit the road for three-game series in Atlanta and Washington.
For more Phillies coverage and opinion, read David Murphy's blog, High Cheese, at www.philly.com/HighCheese. Follow him on Twitter at