Smith (2-1), who was selected out of the University of Rhode Island by the Diamondbacks in the second round of last year's Draft, pitched seven shutout frames and was the winner in Sunday's 5-1 victory over the West Michigan Whitecaps.
He gave up four hits and struck out five without walking a batter to extend his personal scoreless innings streak to 20 consecutive frames.
"One thing I try to work on -- throw more strikes, don't walk guys, let my defense help me out. I have a great team behind me," said Smith, who relies predominantly on his sinker. "We're in the pros now, and I'm realizing every single guy is here for a reason. I get more confident on the mound [every time out]."
Smith fanned the Whitecaps' Jamie Johnson to start the game, and his confidence never dipped.
"Strikeout or groundball or flyout, getting that first out always feels good," he said.
Avisail Garcia led off the second with a single for West Michigan, and two batters later, Luis Salas hit a grounder through the middle. With one out and runners on first and second, Smith turned to his sinker and got Luis Palacios to hit into a double play.
"With our defense, every single guy is just doing their job," said Smith. "I'm starting to pitch with that in mind."
It was the last time two hitters would reach base in the same inning during Smith's outing, and in his last two innings of work, he collected four strikeouts.
"You always want to go more, but everyone's on a pitch count, everyone's on an inning count," Smith said.
South Bend's Matthew Davidson delivered a home run, a double and a sacrifice fly on a four-RBI afternoon to pace the Silver Hawks' offense.
Brian Budrow pitched a scoreless eighth and Rafael Quezada gave up a home run to Jordan Lennerton before closing out the victory in the ninth.
Smith hasn't allowed a runner to cross the plate since Midwest League home run leader Jerry Sands of Great Lakes took him deep in the fourth inning of his first start of the season on April 10.
"The runs I gave up... I just left a pitch up to a great hitter," Smith said, "and he did what he was supposed to do with it."
The 21-year-old also surrendered an unearned run in the third inning of that game, but has otherwise coasted through the beginning of the 2010 campaign. He believes throwing his curveball effectively will be the key to building on that early success.
"I always want to have my breaking stuff working, being a sinkerballer. [That,] I would say, has been my weak point, but it's getting better."
Smith appeared in 12 games across two levels in 2009 -- including three starts for the Silver Hawks -- and went 0-3 despite his 3.64 ERA. He's thrown 24 innings to date in four starts in his first full season, and he's given up 14 hits and one walk while racking up 15 strikeouts. In the meantime, his team has had a turnaround since opening the season with a nine-game losing streak.
"You know, those first 10 games, a lot of us were trying to feel it out and get used to our first long season," he said. "After our first couple wins, we realized we're not as bad as we thought we are. But now we [might not be] as good as we think we are. We're playing really good right now, but we're taking things day by day."