Justin Dunn didn't feel as perfect as he threw Monday. The ball never even left the infield against him.
Seattle's No. 5 prospect set down all 12 batters he faced, striking out eight of them, as Double-A Arkansas clipped Corpus Christi, 5-2, at Whataburger Field.
Video: Travelers' Dunn fans Wrenn
With the temperature in the low 90s before first pitch, Dunn was struggling mightily with command in the bullpen before the game.
"Fastball command wasn't really there, slider was ehh, curveball was loopy and the changeup was nowhere near the plate," he said. "Once I got on the mound, I just kind of turned my brain off and went and pitched."
MLB.com's 75th-ranked prospect started off by striking out the side in the first inning. He then got J.J. Matijevic, Houston's No. 18 prospect, to ground out to second base, fanned Corey Julks swinging on three pitches and retired Jake Adams on a grounder to the mound. Dunn retired Colton Shaver and Osvaldo Duarte on strikes in the third, sandwiched around a comebacker hit by Anibal Sierra.
The 23-year-old capped his perfect start in the fourth by whiffing Bryan De La Cruz and Stephen Wrenn for the second time around a lineout to short by Astros No. 25 prospect Jonathan Arauz.
It marked the first perfect start of Dunn's career and his fourth pro hitless outing. The 6-foot-2 hurler's most recent hitless appearance came during a three-inning stint on May 24, 2017 for Class A Advanced St. Lucie against Bradenton.
After the fourth, Dunn wasn't feeling right due to the heat -- gametime temperature was 91 degrees -- and he mentioned he had a headache and felt dehydrated to Travelers pitching coach Pete Woodworth.
"It felt hotter than that. It's like 75 percent humidity out," he said. "My body didn't feel right and my head was kind of spinning. I want to put my team in a situation to win. I have to make sure my body's all right and I don't overdo."
Gameday box score
But the 2016 first-round pick still threw 36 of his 49 pitches for strikes to lower his August ERA to 3.38 in 26 2/3 innings. In his first year with the Mariners organization after an offseason trade from the Mets, Dunn sports an 8-5 record and a 3.55 ERA with 153 strikeouts and 37 walks in 126 2/3 innings. He leads the Texas League in punchouts and moved into third on the circuit in innings pitched.
Woodworth and Dunn have been working on a mechanical improvement that has helped with fastball command and getting more swings-and-misses on his slider and changeup.
"Cleaning up my direction and getting everything going down the middle of the plate," the righty said. "It started clicking for me this week in the bullpen, so I'm really excited about it."
Arkansas took a perfect-game bid into the seventh behind Dunn and left-hander Matt Tenuta, before De La Cruz tripled on the first pitch of the frame off lefty Aaron Fletcher.
The Travelers waited out a 20-minute delay in the top of the seventh due to a power surge. But Seattle's No. 28 prospect Donnie Walton wasn't bothered. He went 3-for-5 with a run scored, his third multi-hit effort in four games.
Overall, Dunn's been pleased with how his body has held up, enabling him to make 20-plus consecutive starts for the first time as a pro, and the stats he's been able to post this year.
2019 MiLB include
"They just wanted me to come in and perform," he said. "I really appreciate their philosophy of letting me be my own pitcher and get back to being who I was, being athletic and just letting me do what works for me."
Dunn set three goals for himself before the season. Make an All-Star team -- he pitched one scoreless frame in the Texas League's midseason classic on June 25 -- play in the Futures Game -- he hurled another scoreless inning in the All-Star showcase on July 7 -- and reach the Major Leagues.
"We're on the right track so far," he said, "but one more to finish up."