Before that sequence, Keuchel was nearly untouchable, retiring the first 15 hitters through five innings and allowing only two balls to leave the infield, a credit to his sinker and changeup, according to Castro.
"I think it was a mixture of me feeling good and their aggressiveness was helping me out," Keuchel said. "Those first couple innings set the tone for the last three."
"Earlier on, he had a hard time going to the glove side of the plate, he was kind of fighting that all game," Castro added. "He made a few pitches there with his cutter and a few sliders."
Keuchel lamented the sixth, when he said he ran out of gas, leading to two runs on consecutive RBI singles from Troy Tulowitzki and Nolan Arenado.
Houston manager A.J. Hinch yanked Keuchel in the seventh after Hundley's two-out RBI double cut the Astros lead to 5-3, though Keuchel's first five innings left Hinch heaping praise after the victory.
"I thought early on he was as sharp as he's been all year," Hinch said. "Getting ground balls, getting soft contact. He was really in command of himself. ... He was terrific and did what Dallas does. "
Castro disagreed with his manager only slightly.
"I don't know if I'd say that's the sharpest I've seen him," Castro said. "That's the Dallas Keuchel we've come to expect."
Chandler Romer is an associate reporter for MLB.com.