"It all started with [fastball command] and it allowed me to really get the breaking ball going," Duffey said. "They're a pretty aggressive team, and that plays into my game if I'm throwing good sinkers that day and breaking balls there."
Duffey, who has struggled with the mechanics of his three-quarters delivery in his bad starts, felt much more comfortable with his pitching motion against the Astros, and the results showed. He allowed only four hits and threw 62 of his 95 pitches for strikes.
Seven of Duffey's eight strikeouts were of the swinging variety, with all seven coming on the curveball. He also induced eight groundouts against only two outs in the air, a welcome turnaround for the sinkerballer after he yielded nine groundouts against 20 flyouts over his last two starts.
"I feel like I've been more consistent, and that's the big thing -- with my arm slot, release point, stuff like that," Duffey said. "It feels really good. It felt strong, and stuff was going where I wanted it to. That's the biggest thing."
He was the latest pitcher to stifle Houston's struggling offense, which has scored only 32 runs in its last 14 games while hitting .201 as a team in that span. Duffey has pitched well against his hometown Astros in both of his career starts against them -- he struck out eight and allowed two runs in a 6 2/3-inning outing last season.
Duffey only ran into trouble in the sixth inning, when he walked Tony Kemp and allowed a single to Alex Bregman before an RBI double from George Springer brought home Houston's only run.
But after a mound visit from pitching coach Neil Allen, Duffey buckled down, getting a groundout from Carlos Correa and a big strikeout of Evan Gattis to strand a potential tying run at second base.
"I knew Correa was going to be swinging, so I just wanted to throw a good breaking ball over the plate," Duffey said. "I got the ground ball and got out of it with just the one run. That was big for us. We'd just scored and I needed a quick inning for us. Fortunately, I was able to get out of it."
Do-Hyoung Park is a reporter for MLB.com based in Minneapolis. This story was not subject to the approval of Major League Baseball or its clubs.