After spending this April with Class A Rome, where he posted a 4-1 record and 3.72 ERA, Sullivan put up a 5.25 ERA through his first four starts after his promotion to the Class A Advanced Carolina League.
Whatever was troubling him, he seemed to put it behind him on Wednesday.
"I changed my mindset a little bit," said Sullivan. "I was a lot more aggressive [Wednesday]. I attacked the zone with a lot more confidence and focus."
"Those first four starts, I was just settling in. Getting used to my surroundings," he added.
Sullivan struck out Winston-Salem's Dale Mollenhauer to start the game, and coasted through the third without allowing a hit. However, he said he didn't allow the notion of throwing a no-hitter to enter his mind.
"In the dugout, I was just thinking about throwing strikes. I wanted to make sure I kept getting ground balls."
Greg Paimi led off the fourth with a single, but Sullivan induced an infield popup off the bat of Jim Gallagher and struck out the next two he faced.
"My movement was good," Sullivan said. "I was focused on working in and out with my fastball all game. This game felt the best I've felt all season."
Lee Cruz lined a single to left to start the fifth. After a groundout and another strikeout, Sullivan walked C.J. Lang, marking the only instance all game when two Dash runners were on base at the same time. Sullivan got Mollenhauer to tap a ground ball to first to end the inning.
Sullivan faced Cruz again in the seventh, and he was determined not to be affected by Cruz's previous at-bat.
"I just was trying to work inside and outside on him, trying to get him to hit a ground ball," Sullivan said. "But he knew the fastball was coming. I left it over the plate a bit, and he hit it pretty well."
Cruz smacked a line drive deep into left field. As Cruz rounded second, Cole Miles threw the ball to shortstop Chad Lundahl, who relayed to third baseman Donell Linares. Linares put the tag on the sliding Cruz for the second out of the inning.
"That was a huge play. That changed momentum for us and got me out of [what could have been] a jam. Our defense was [darn] fine."
Sullivan worked a perfect eighth and ninth, fanning the last batter, Salvador Sanchez. The third strike, though, careened off catcher Matt Kennelly's knee to the backstop. Kennelly hustled to the ball and threw Sanchez out.
Having benefited from his teammates' defensive skills all game, Sullivan found Kennelly's strong play a satisfying way to close out the ballgame.
"I can't say enough about the defense behind me," said Sullivan. "Kennelly did a good job getting to the ball there, so that was a really appropriate ending."
"After the game," he said, "they gave me a pie in the face. But it wasn't a pie. It was shaving cream. We're all having fun, the whole team."