Nobody who has been around him all season was surprised.
Long before the Heat started dominating the rest of the league in the postseason bubble -- Miami is just one game from its first Finals appearance since 2014, with a 3-1 series lead over Boston -- teammates and coaches were singing Herro's praises. They always believed that he was capable of big performances on the biggest stage, they always trusted that he wouldn't shy away from the moment, and they always knew that the 20-year-old had confidence well beyond his years.
"Not too many people get an opportunity to make it this far in the playoffs and to be in a game like this," Heat All-Star swingman Jimmy Butler said. "But for him, it's another day at the office. I think it makes all of us smile. We're all so happy for him because he knows what he's capable of, and he just plays with so much confidence. He's been doing it all year long. So to him, there's no pressure or anything. He's just going to keep playing basketball the right way."
As the rest of the basketball world shook its collective head in amazement at Herro's 14-for-21 shooting effort, including five 3-pointers, the Heat took his latest feat in stride because they saw it coming. To the personnel who watched Herro work in the gym day after day over the past year, his success doesn't come as a surprise.
"I know like everybody is looking for that signature moment," Heat coach Erik Spoelstra said. "That would be such a great story, right: 'I knew that day he would be this guy.' I think everybody overestimates what you can do in a day and what you can do in months of work and sweat and grind when nobody is watching. He is relentless with his work ethic.
"Nobody was paying attention to us during the year. He had a lot of tough moments. He did. He had some moments where it was up and down and learning about our demands on defense. But he is a worker, and he shows up the next day trying to get better every single day, and usually those incremental improvements every single day, and he earns the trust -- I think it's more important earning the trust of his teammates than the coaching staff, but it's that daily grind when nobody is watching and doing it when most people don't."
As usual, the mild-mannered Herro answered questions with the same calm demeanor that he used to drain big shot after big shot for a defense that never found an answer to keep him in check. Herro's 37 points are the most scored by a rookie off the bench in a playoff game since 1971, according to Elias Sports Bureau research. They are the second-most points scored by a player age 20 or younger in NBA playoff history. The only player who scored more at that age was Los Angeles Lakers legend Magic Johnson.
"I'm just going to bet on myself," Herro said. "I've been doing that my whole life. I went from a small town in Milwaukee to Kentucky, and nobody thought I would survive there, and nobody thought I would survive here. At the end of the day, it's just betting on myself."
The "bet on myself" mantra is familiar to Butler, who used a similar personal ethos to elevate himself into one of the best two-way players in the game, consistently breaking through barriers that other people set in front of him. The pair clicked almost instantly after the Heat drafted Herro out of Kentucky, bonded by a hard-working passion for the game that Butler always wanted to see in younger players in his previous NBA stops. Herro said earlier this season that he reached out to Butler via Instagram last summer, and Butler invited him to Chicago so they could work out together. The relationship has grown since then.
"He just fits in here," Butler said. "I think everybody got that chip on our shoulder on our roster, in our organization. But he's coming into his own. He will continue to grow. I said it earlier in the year: Miami is going to love him. They are going to fall in love with him. I know that they are, and I know that they have. He's key to us going forward for a lot of years to come."
Herro has repeatedly praised Butler for the impact the 31-year-old has had on him on and off the floor.
"Jimmy, ever since I got here, he's been like a big brother to me," Herro said. "And he's shined light on me. He's taught me a lot of things. He's just continuing to get on me. Whether it's something I want to hear or not, he's going to tell me what I need to hear. I appreciate him for that."
The appreciation for Herro was high after Wednesday's win.
"First of all, I don't believe he's 20, how he's playing," veteran Heat guard Goran Dragic said with a laugh. "We believe in him. Everyone believes in him. That's why we're not afraid to put the ball in his hands."
All-Star big man Bam Adebayo shared a similar sentiment.
"First of all, I haven't been surprised because I knew what the kid could do," Adebayo said. "I was the one who put the bug in Pat [Riley's] ear to draft the kid. Just saying. I'm not shocked by the success that Tyler's having. He comes in the gym every day, great work ethic, great dude, he doesn't bother anybody, just works."
Aside from the excitement surrounding Herro's game, the only real pause came with 2:06 in regulation in the wake of Adebayo's getting tangled up with Celtics guard Jayson Tatum. Adebayo's left wrist appeared to get turned in the wrong direction, but he brushed off concerns about an injury.
"I'm good," Adebayo said. "Just a wrong turn ... wrong little movement, nothing major."
Spoelstra said there was no update on Adebayo's status but didn't sound concerned.
"He's just got a lot of ice on his body," Spoelstra said. "And that's where we are right now: Everybody's earning their ice."
What Herro has earned is the type of universal respect usually bestowed upon players much older. His teammates and coaches never needed a reminder, though. They thought he was capable of this from the start.
"You know we are all going to absolutely crush him tomorrow to keep him humble," Spoelstra said. "But I say that kiddingly because he has a great, competitive humility about him. He has a confidence. He has a fearlessness that is uncommon. But he's humble enough to work, to be coachable, to take the mentorship from the veteran players that we have on our team, and he just continues to gain more confidence as we go. I think the second training camp here, I think, was a big benefit to him because it felt like he was going into his second year in many ways."