MILWAUKEE -- Zack Greinke worked another Miller Park masterpiece on Wednesday, begging two questions:A free-agent-to-be, how could he even consider pitching anywhere else? And how could the Brewers ever let him go? With his team sputtering to start a crucial homestand, Greinke remained perfect at home, buoyed by the Brewers' four-run fourth and Taylor Green's first Major League home run on the way to an 8-0 win over the Cubs. Greinke set a season high with 12 strikeouts over seven innings. He allowed only two Cubs hits, including an Alfonso Soriano double in the second inning that might have been ruled an error had it not glanced off third base. Greinke improved to 15-0 at Miller Park, only the fourth pitcher since 1900 to win at least his first 15 home decisions with a team. With one more such win, he would match a Major League record held by the Yankees' Johnny Allen (1932-33) and the White Sox's LaMarr Hoyt (1980-82), each of whom won their first 16 home decisions with those clubs. Greinke will have to wait, because his next start comes Tuesday in Kansas City, where Greinke made his mark. The Brewers are 20-1 when Greinke takes the mound at Miller Park. Yet unless something dramatic changes in the stalled talks between his agent, Casey Close, and the Brewers, Greinke will hit the open market after the World Series. "I'm sorry, I'm not talking about anything to do with after this year," he said. "It's just this year right now." So he talked instead about his remarkable run in Milwaukee, again citing the Brewers' offensive support in his home starts. That offense was sparked Wednesday by right fielder Norichika Aoki, who scored twice and had three hits, including a double that started the decisive fourth inning. But Greinke has also pitched well here, evidenced by a 2.50 ERA in his 21 Miller Park starts since the trade. He ran down the reasons for his home success once again on Wednesday night: The comfort of sleeping in a familiar bed, the routine ride to the ballpark and the spacious home clubhouse with room to prepare for a start in peace. This time, though, Greinke came up with a new reason: Coffee control. "Sometimes in the hotels, they have bad coffee," he said. He was serious. For Greinke and plenty of other ballplayers, it's all about routine. "It helps a lot in making you comfortable," he said. On Wednesday, the teams were scoreless into the fourth inning, when Aoki led off with a double against Cubs starter Paul Maholm. The left-hander slipped to 3-10 in 21 career starts against the Brewers, most of them with the Pirates. Aoki, Ryan Braun and Cody Ransom all doubled off Maholm during the Brewers' big inning, Braun's the hit that put the Brewers on the scoreboard and Ransom's a run-scorer that made it 2-0. Brooks Conrad followed with a two-run single, only his third Brewers hit and the first that was not a home run. "That was a great inning," manager Ron Roenicke said. "Offensively, we had some nice at-bats today." The challenge is sustaining it Thursday against the Cubs' Matt Garza. "That's been the challenge the entire time, sustaining good baseball," Braun said. "Getting contributions in all facets of the game on the same day. We've had plenty of glimpses, flashes, where we've played really well." The Brewers added an unearned run in the fifth inning, by which time Greinke was in control. After loading the bases in a 30-pitch second inning, he struck out Maholm to begin a stretch in which Greinke whiffed nine of 11 batters. The Cubs struck out 15 times in all, one night after whiffing 14 times in their series-opening 10-0 win. "If you're going to strike out that many times in back-to-back nights, you're not going to put many runs up, that's for sure," Cubs manager Dale Sveum said. "Greinke, that's about as good as he's going to get down in the zone. He had command of all his pitches. That was pretty dominant, obviously." Greinke was pitching mad during his strikeout stretch after his long second inning. As he walked off the mound after that frame, cameras caught Greinke exhaling in frustration. "That was really bad pitching on my part," he said. "I was mad about it, probably for a couple of innings." He was mad about issuing a two-out walk to No. 7 hitter Darwin Barney after getting ahead in the count, 1-2. He was even more upset after walking the eight-hole hitter, Ian Stewart, and then nearly balked in a run when he crossed signals with catcher Martin Maldonado with Maholm at the plate. It was an 0-2 pitch that went in the books as a 53-mph curveball. In truth, Greinke started his delivery aiming to throw a fastball, then realized mid-move that Maldonado had called a curve. Rather than balk home a run, Greinke did his best to fling a pitch toward the plate. "That's how the inning was going for me," Greinke said. "It definitely wasn't real sharp." It took three more pitches after the misfire for Greinke to catch Maholm looking at a 94-mph fastball for strike three. "I ended up wasting about 20 pitches in the process," said Greinke, who wound up throwing 109 pitches total. Green's first career homer was a three-run shot in the eighth.