Hahn went to work in opposition of Angels starter JC Ramirez, who countered with seven scoreless innings in just his third Major League start, and put together an outing better than any the A's have witnessed from him in years.
The right-hander twirled eight shutout innings of one-hit ball, inducing 12 ground-ball outs. He struck out six, walked two and enjoyed his longest outing since he tossed a complete game against Detroit on May 25, 2015.
"I feel like I literally had everything working for me today," Hahn said. "I think it might have been the best command I've had of my pitches."
Hahn established his fastball command right away, finding a rhythm with his sinker as the Angels littered weak ground balls across the infield. Only in the fifth inning did something harder sneak into the outfield, when Andrelton Simmons singled for the Angels' only hit off the right-hander.
Hahn promptly picked off Simmons, retiring 10 of his final 11 batters with assist from right fielder Matt Joyce, who robbed Jefry Marte of extra bases with a diving catch to open the eighth inning.
"He threw a great game," Melvin said. "You look right away and look at all the ground balls. He pitched as well as we've seen him, had his best sink of the year, by far. Best sink in a while, and a good curveball. Really had it working tonight."
Hahn has allowed just four earned runs across 20 innings over three starts since he was reinserted into the rotation, surely offering pause for thought as the A's mull over roster choices leading up to the returns of starters Kendall Graveman and Sonny Gray in the next week.
"He's been good, and each time you gain a little more confidence," Melvin said. "That was one of the better performances we've seen of him since he's been here."
Jane Lee has covered the A's for MLB.com since 2010. Follow her on Twitter @JaneMLB.