"[It's] just really a validation for the work you put in and the years that I've been here," said Wainwright, who has started a season opener three times previously.
"I saw [Chris Carpenter] do it, and I've seen the number of times that [Bob] Gibson did it. Each time I get to, it's just a very special thing. It's an assignment that they don't hand out lightly, and I think that's why they waited until the last couple days to announce it. It's a great privilege [for] me."
There was never a question about who the Cardinals wanted to showcase in their opener, but Wainwright first had to prove that he could get ready amid an altered spring program.
An abdominal strain he suffered a few days before camp opened kept Wainwright off the field for conditioning work and fielding drills until March. He continued to throw on the side, but the Cardinals didn't have Wainwright make his first Grapefruit League appearance until March 21.
That gave him just enough time for three starts, the last of which came against the Marlins on Tuesday in the Cardinals' 3-2 loss. The Marlins led off each of the first five innings with a hit, though Wainwright worked around most of the trouble. He allowed two runs, only one of which was earned.
"I felt like I got better as I went," Wainwright said. "I'll continue to do that, hopefully, in the season and all the way into the postseason. The last game, I was not where I wanted to be so I knew I had to make some adjustments. I'll continue to do that. I felt much better, especially [with my] fastball command. The bite on my slider and curve are getting better. They're not 100 percent where I want them to be yet. But I didn't waste any bullets in Spring Training, that's for sure."
Wainwright threw 93 pitches in the effort, putting him on track to be able to shoot past the 100-pitch mark in his season debut. In total, he allowed 18 hits and five earned runs in 14 1/3 spring innings. He walked three and struck out seven.
And now he knows, officially, what he'll be doing next.
"We know what he does on a big stage and how he rises to the occasion of big opportunities," Matheny said. "Opening Day is a big opportunity."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, follow her on Twitter @LangoschMLB and like her Facebook page Jenifer Langosch for Cardinals.com. This story was not subject to the approval of Major League Baseball or its clubs.