Garza (3-5) pitched good enough to win, allowing only three runs on five hits, while striking out seven and walking one in seven innings.
But the Cubs had only four hits, and just three off of Miley, who ran his record to 9-3. Miley solidified his position as the probable D-backs delegate to the National League All-Star team by striking out seven, walking one and tossing 116 pitches in eight innings.
This was the nexus of the game: With the D-backs leading just 3-1, the Cubs had runners on second and third and no outs in the eighth after Geovany Soto walked and Darwin Barney doubled. Miley, though, pitched out of the jam, retiring the next three hitters. Joe Mather struck out, pinch-hitter Luis Valbuena lined to short and David DeJesus bounced back to Miley.
For Miley, it was his sixth win in his last eight decisions.
"We get guys on second and third and we can't even make contact," Cubs manager Dale Sveum said. "That's been the biggest key, striking out so many times in these situations especially when there are less than two outs. We're not even moving anybody."
The Cubs are 14-19 at home, and are now 10-29 on the road. They are anticipating the arrival of Rizzo sometime during this six-game homestand against the Mets and Astros, but even that may be no panacea.
"We've got to start doing something against left-handed pitching or else it's going to be a long homestand," Sveum said. "Reinforcements? I don't know what the date is and what reinforcement were going to get. At least we know we're going to get one, but when that date is I don't know yet."
Rizzo is currently a .349 hitter with 23 homers and 63 RBIs for Triple-A Iowa. But he has already proven he can tear up the Pacific Coast League. Last year, he hit .331 with 26 homers and 101 RBIs for Tucson.
But when his much ballyhooed ascent to the Padres came, he couldn't hit big league pitching. Rizzo batted .141 with a homer and nine RBIs in two stints playing for San Diego. The homer came his first weekend at Petco Park. He was brought up on June 9, 2011, and barely lasted a month. He returned in September, and was traded to the Cubs during the offseason.
At 22, Rizzo has a year more experience and anything could help the Cubs, who are 27th in the Majors with 264 runs scored.
"You've got to score runs, and that's the bottom line," Sveum said. "We don't score a whole lot of runs. When we score four runs or more we're over .500. But that doesn't happen too often. There's too many times when you have one run. You're not going to win many games that way."
Garza was on that end, trying to win with that one run of support on Sunday. Garza walked Gerardo Parra, Arizona's leadoff hitter, in the opening inning and he came around to score the game's first run on a Justin Upton single. Garza said he hung sliders to Parra and Jason Kubel that led to the other runs scored against him.
Parra tripled with two outs in the sixth and scored on Aaron Hill's infield single, and Kubel opened the seventh with his 10th homer.
"We knew he had good stuff today, so for us to be able to scratch a couple runs across early on a couple hits, those were big contributions," D-backs manager Kirk Gibson said after his now 37-35 club went 5-1 on the just-concluded homestand.
Garza has only come up on the winning end once since April 29. And that was in his previous start, when he allowed only five hits and three runs to the White Sox last Monday at U.S. Cellular Field. It wouldn't be his fate to win again on Sunday, though.
Garza said the Cubs will weather this period of adversity.
"We show up every day and we play," he said. "We show up and we work. We're not quitters. We're going to keep fighting, keep going, keep clawing. That's all we can do. I always say, I'm getting ready for the next one."
The next one might include Anthony Rizzo, or perhaps the one after that or the one after that.