"It was a slider, middle-up," Cueto said of the mistake pitch. He wanted it down and away.
Hall is a .313 (75-for-240) hitter lifetime against the Reds. His 16 homers and 45 RBIs are by far his most against any opponent since he entered the Majors in 2002.
"He hurt us in Chicago, too. You make a mistake, he doesn't miss it," Reds manager Dusty Baker said after his club opened a nine-game road trip with the loss.
Cueto finished with two earned runs and five hits allowed over 6 1/3 innings. He struck out eight and threw 66 of his 96 pitches in the game for strikes.
"He was throwing strikes, quality strikes," Baker said. "He only made one mistake tonight."
Like his brilliant 10-strikeout, seven-inning Major League debut on Thursday vs. Arizona, there were no walks on the 22-year-old right hander's pitching line. He changed speeds often, with his fastball running between 92-96 mph and topping out at 97. He also ran upper 80s sliders and had a changeup down in the low 80s.
"I did throw more sliders today, but I was pitching the same [way] I pitched last time," said Cueto, who has 18 strikeouts and a 2.02 ERA through his two starts.
In the sixth, with one out and a runner on second, Baker let Cueto bat rather than go with a pinch-hitter. It was a risky move with the Reds in need of a run.
Baker did not waver in the decision to stick with Cueto.
"He deserved a shot to win this ballgame," he said. "That was his last inning -- the seventh -- anyway."
After Cueto grounded out, Corey Patterson hit an RBI single that tied the game. Hall's homer in the seventh gave Milwaukee a 2-1 lead, but Patterson came through again in the top of the ninth.
With Eric Gagne on to close for the Brewers, the Reds were down to their last strike when Patterson tied the game at 2 with a solo home run that barely cleared the right-field fence.
Against Reds reliever David Weathers (0-1), J.J. Hardy started the Brewers 10th inning with his third single of the night. Two of his hits were off of Cueto. Not bad for a guy who came into the game batting .105.
"He wasn't swinging like that tonight," Baker said. "He found something that got him straight."
Hardy moved to second on Joe Dillon's pinch-sacrifice bunt. Jason Kendall's third single of the game put runners on the corners. With one out, the Reds had to play their infield and outfield in.
That enabled Weeks to punch a rolling single past the shortstop and end the game in walk-off fashion.
Brewers starter Jeff Suppan held the Reds to one earned run over six innings, but the Reds had some chances. Cincinnati was 1-for-6 with runners in scoring position and stranded 11 baserunners in the game.
The best chances came after Suppan's departure. The bases were left loaded in the eighth. The lineup's Nos. 4-5-6 tandem of Brandon Phillips, Adam Dunn and Edwin Encarnacion combined to go 0-for-11 in the game.
"We fought and battled," Baker said. "We had a lot of opportunities. That big hit kept eluding us."