Hynick yielded one run on six hits over six innings as the Drillers shut down Springfield, 4-1, to force a decisive fifth game in their Texas League semifinal series.
The 27-year-old right-hander said he didn't feel like he had his best stuff. But he struck out five, walked two, got support from his defense and was able to fight his way to the win.
"It was a battle. I wasn't in the zone as much as I'd like to be," he said. "I just told myself to let the defense work, and they did, they did a hell of a job.
"It was a tough night. I didn't have the feel that I would like to have, was falling behind a lot. But I got into some situations where I got some ground balls. and they were back there behind me. It was all them."
Hynick (1-0) became a reliable member of the Tulsa rotation this season after a demotion from Triple-A Colorado Springs. He went 7-3 in 12 Texas League starts, posting a 2.11 ERA with 51 strikeouts and 18 walks over 81 innings.
Tulsa fell behind in the best-of-5 series, 2-1, after Springfield posted a 4-2 win on Friday night. But, as has been their pattern through at least four games, the Drillers responded with a strong pitching performance and just enough offense to draw even.
Hynick said the only thing he could do as a starter was approach the game like any other, despite the raised stakes.
"I tried ... not put any extra pressure on myself," he said. "I'm trying to win every game I go out there and pitch, so you treat it the same, just compete.
"We're really excited right now, have some momentum going into Game 5 and feel like we have a chance to win the whole thing."
Offensively, Tulsa got production from its No. 7-8 hitters. Center fielder Chris Pettit smacked a two-run homer in the second inning and Tim Torres went back-to-back to give Hynick an early 3-0 lead.
Corey Dickerson went 2-for-5 with a double and an RBI and Rockies top prospect Nolan Arenado also had two hits.
Zach Simons walked one and struck out two over two innings and Coty Woods pitched around a hit in the ninth to record his first postseason save.
Game 5 is Sunday afternoon in Springfield and Hynick said he expected it to be characteristic of the rest of the series -- tight and down to the wire.
"We expect to win every time out there, but we have to take it one pitch at a time. That's a cliché but it's true," he said. "Try to get runs when we can, prevent runs when they do get guys on base. We've got two good teams here who've been fighting all year. No one's gonna lay down, it's gonna be a battle. But we have confidence."
Xavier Scruggs supplied the Cardinals' offense with a second-inning homer.