The Rays prospect went 2-for-4 with two RBIs for the Surprise Saguaros as they defeated the Phoenix Desert Dogs, 6-2.
"My approach going in was to stay middle and get a good part of the bat on the ball," Mahtook said. "Fortunately, I was able to get some good pitches."
After hitting .383 with 14 homers and 29 steals in 56 games during his junior season for Louisiana State University, Mahtook was selected with the 31st overall pick in the June Draft. In five AFL games, the 21-year-old outfielder is batting .263 (5-for-19) with a steal and five RBIs.
"It feels really good," Mahtook said. "It's been about four months since the college season ended, and I didn't play in the summer. Being back in a uniform, back with a team feels great. The AFL is a great league, and I'm honored to be chosen as a guy to play here."
Marlins outfielder Kevin Mattison also enjoyed a two-hit game for Surprise, tripling and scoring twice out of the leadoff spot.
Phoenix's two runs were driven in by a pair of Reds prospects. Brodie Greene homered to begin the fifth and Cody Puckett followed with an RBI single five batters later.
Starter Nathan Adcock (Royals) earned the win for the Saguaros, striking out seven over three scoreless innings.
His opponent, David Phelps (Yankees), took the loss after surrendering three runs on four hits over three frames.
Overall, Mahtook's goal for the fall is just to get used to playing baseball regularly again.
"I haven't played in a while, so I'm just getting as many at-bats as possible and getting acclimated with pro ball life," he said. "Obviously, I want to work on every aspect of the pro game."
Though he comes with the first-rounder label, Mahtook said he does not feel additional pressure on the field.
"Not at all," he said. "Being a first-round pick has that status, but it's not something that puts pressure on me. Baseball has been a game I've played my whole life -- the game is fun."
David Heck is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.