Houston's No. 6 prospect scattered two hits and four walks while striking out seven over six scoreless innings to pitch Class A Lexington to a 3-1 win over Hagerstown and earn his South Atlantic League-leading 13th victory.
Foltynewicz (13-3) had allowed more than three earned runs in a start just three times in his first 19 starts this year, then did it in back-to-back outings July 21 and 26.
The right-hander responded well, though, tossing five two-run innings July 31 and then spinning an unblemished effort Monday.
"It gets my confidence back after those two," said the 20-year-old. "You have to finish strong. The playoff race is around the corner and I just want to go out there for my team and win. It's big for the confidence really."
Foltynewicz also had struck out at least seven batters only twice prior to his last two outings, when he fanned eight and then seven on Monday.
It's a sign of maturity from the 19th overall pick in the 2010 Draft that he was able to follow up two of his worst outings this year with arguably two of his best.
"I've just mentally grown. Last year, I had a temper, but you have to shake it off and throw the next pitch," he said. "I've done a lot of growing up, I feel mentally tougher.
"That's been a big process for me. I had to get used to it, since I'm a competitor and things frustrate me. But you just have to keep that inside and go out there and make that next pitch."
The Minooka (Ill.) Community High School product said on Monday his two-seam fastball paved the way for most of his success, as he kept it low and managed to generate a good amount of weak ground balls. His curveball and changeup also figured in as well, he added.
On the season, Foltynewicz has a 2.93 ERA, good for fifth in the Sally League. His 132 innings represent the league's largest workload, and he has the circuit's eighth-most strikeouts with 103 against 52 walks. His 13 wins are tied for third-most in the Minors.
It's been a marked improvement from last year, when he went 5-11 with a 4.97 ERA in 26 starts for the Legends.
"I'm real happy, it's been a big step from last year," he said. "I worked on a lot of things in the offseason to get where I am today and I'm really happy with the way I'm pitching. The defense and hitting have helped me out tremendously. Overall, it's been a great year."
Offensively, Delino DeShields Jr. plated a run and scored once for the Legends. He also stole his 81st base of the season, second-most throughout the Minors only to Pensacola's Billy Hamilton. Nolan Fontana and Emilio King drove in the team's other two runs.