Mitch Keller was jonesing to make this start for a week.
The Double-A Altoona right-hander had two rough outings against Harrisburg -- allowing nine runs on 14 hits with six walks and three long balls over 10 frames -- so Keller was chomping at the bit to face that lineup again. He made the most of his opportunity Monday.
The top Pirates prospect allowed a hit and a pair of walks while fanning six over a season-high eight innings in the Curve's 4-0 shutout of the Senators at Peoples Natural Gas Field. It was his regular-season professional best, since he threw a one-hitter in the Eastern League semifinals last Sept. 7 en route to the Eastern League crown.
Video: Keller picks up his sixth K for Curve
"I was looking forward to this one for sure and it felt really good to go after them after two bad outings," Keller said. "I felt really good. I had a good gameplan today and I felt like I was in the zone from pitch one. I was ready to get after it."
The 21-year-old won his fourth straight outing and has not taken a loss since May 9. Keller (9-2) has lasted at least six frames in his eight starts since then, not giving up more than two earned runs seven times -- including three outings without one. His ninth victory also tied his single-season career-best mark.
Gameday box score
"I think it was just a matter of getting that attack mentality back," Keller said. "Not that I ever lost it, but it just needed a little refined focus. But I've also been fluid with my mechanics and I've been able to throw it where I want it in any count and that's huge."
MLB.com's No. 14 overall prospect faced the minimum 15 batters through his first five innings on just 46 pitches. After allowing a single to right field by third-ranked Nationals prospect Carter Kieboom with one out, he induced a 4-6-3 double play off the bat of third baseman Jake Knoll to end the first frame.
"Everything was working," Keller said. "I was able to attack with my fastball, the breaking ball was on, my changeup was there and the defense was unbelievable. They made a lot of plays and turned two whenever I needed it."
Video: Tucker shows hops to snag DP for Curve
Keller walked Adam Brett Walker after a nine-pitch at-bat to start the sixth, his first three-ball count of the game, then faced the minimum -- nine -- the rest of his outing. Pirates No. 5 prospect Cole Tucker made a full-extension leaping grab to take a hit away from Washington's No. 22 prospect Drew Ward in the seventh. The shortstop then fired to first to catch Noll wandering too far off the bag to end the inning.
"That play by [Tucker] was huge. Who knows what happens after that if he doesn't make that play and how many more pitches I have to throw. I might not have come out for the eighth," said Keller, who finished with 92 pitches (58 for strikes) after needing 25 to get through the sixth and 10 in the seventh. "It was a [heck] of a catch and a heads-up play to throw to first."
Keller's fastball remained in the 93-97 mph range and his curveball showed bite at 80-82 mph. No Harrisburg runners advanced into scoring position the entire game.
"I just wanted to go out there and execute my gameplan because I didn't really execute it well the last times against these guys," he said. "I was able to do that and the offense was awesome too. They were hacking away all night, getting 11 hits. I think you feed off the hitters and they feed off me, it goes hand-in-hand."
Right-hander Montana DuRapau completed Altoona's fifth shutout after retiring the side in order in the ninth. It was also the ninth time Harrisburg was held scoreless.
Pittsburgh's No. 21 prospect Jason Martin collected three hits -- including a double -- and scored twice while Christian Kelley doubled in a run.