The frustrated grimace Casey Mize wore on his way off the mound Wednesday night reflected his disappointment over a two-run lead that vanished. He might have been the only person connected to the Tigers with that face.

Fortunately, it was temporary.

“I'm not going to lie to you: I had a blast out there,” Mize admitted afterward. “That's the most fun I had playing baseball, ever.”

As frustrating as the Tigers’ eighth consecutive loss proved to be in a 5-3 defeat to the White Sox, the enthusiasm not only was understandable, it was shared. This was the moment Tigers fans and personnel had anticipated ever since Detroit drafted Mize first overall in 2018. This was the moment Mize had been working toward his entire life.

• Box score

Mize didn’t get a decision, but his 4 1/3 innings left an indelible impression on the Detroit sports scene as well as the record books.

Never had a Tigers starter struck out seven or more batters without a walk in his Major League debut. No Major League pitcher had done it since another No. 1 overall pick, Stephen Strasburg, debuted for the Nationals on June 8, 2010. Mize’s splitter, which he deployed on Yoán Moncada for his first Major League strikeout on his second big league batter, became a highlight pitch. And Tigers fans found a must-watch pitcher.

• Prospect debuts; H. Castro to IL

“We all know that the kid's a really special talent,” manager Ron Gardenhire said. “He's going to take a few bumps here and there. He didn't really have much of a bump tonight.”

Asked a day earlier what he expected of himself, Mize said he expected to give his team a chance to win like always, but that he also expected to have a lot of fun. The former Auburn standout kept up his end of a pitching duel with fellow White Sox debutee and former SEC rival Dane Dunning before José Abreu and Edwin Encarnación homered off of Gregory Soto in the eighth to break a 3-3 tie.

The fun part didn’t show on Mize’s face as he worked through a White Sox that has punished Tigers pitching for much of the last week and a half. Still, that willingness to enjoy the moment helped him control his nerves.

“I was really thankful for the opportunity to be back out there and just try to compete for something. It's been a long time since I've been able to do that,” said Mize, who hadn’t pitched in a regular-season game in a year and two days since his final start at Double-A Erie last season. “And it's also just where I wanted to compete at the highest level since I was a kid. So all those things, it just made it so much fun. And pitching well early on just obviously helped that. So I really did have a blast, and I competed my tail off. And obviously not happy with the total outcome, but I did some things really well tonight that I'm going to build on and continue to do that.”

The Tigers knew he had the stuff to compete, having seen him in their last two Spring Trainings before he dominated hitters in Summer Camp last month. Even so, catcher Grayson Greiner said Mize’s splitter Wednesday was the best he had seen it.

“Even in the bullpen pregame, we knew it was going to be a pitch we could go to early and often,” Greiner said. “He got a lot of his strikeouts on it, a lot of weak contact ground balls on it.”

Mize racked up two strikeouts in the first inning, then rebounded from Encarnación’s leadoff homer in the second to hold the damage there. His splitter completed an eye-opening three-pitch strikeout of Tim Anderson to begin the third inning, then a four-pitch strikeout that prompted a nod of respect from Abreu.

Dunning, drafted two years before Mize out of Florida, outpitched him early, striking out six of Detroit’s first 10 batters with a sharp breaking ball. The two conference rivals combined to strike out 11 of 22 batters through their first three innings.

"I thought that was really neat, really cool how we're both making our debut,” Dunning said. “Pretty sure we had similar lines, as well. I thought that was really cool how that played out."

It was also historic. Never in modern MLB history -- at least since 1901 -- had two pitchers making their debuts in the same game each put up seven or more strikeouts.

"[Dunning] obviously had a very good start, and he was pretty efficient,” Mize said. “We were kind of getting back out there pretty quick with each other. So I think that helped the flow of the game, and that helped us stay in our rhythm.”

That ended in the fifth. Jeimer Candelario’s three-run homer in the top half gave Mize a lead to protect and chased Dunning, but Zack Collins’ leadoff double off a hanging splitter was a warning sign. Mize fanned Adam Engel on a fastball, but Anderson’s seeing-eye RBI single and stolen base set up Moncada’s game-tying single.

“His splitter was not doing too much at the end,” Gardenhire said. “and I'm sure that was the adrenaline flow.”

The blown lead frustrated Mize and another loss flustered Greiner. Still, the catcher knew what the moment meant.

“I think he's going to be a very good pitcher for a long time,” Greiner said. “Hopefully when he tells his grandkids about his debut, he talks about the catcher a little bit.”