Tyler Herro saluted "big brother" Jimmy Butler after taking the Miami Heat to the brink of the NBA Finals, and took a swipe at his own doubters.

The 20-year-old Herro led scoring for the Heat with a career-high 37 points in a 112-109 win over the Boston Celtics, securing a 3-1 lead in the Eastern Conference finals.

Now the former Kentucky Wildcats prodigy, who was the 13th overall pick in the 2019 NBA Draft, could cap a first season in the professional ranks with an appearance in the championship series.

He had 37 points on 14-of-21 shooting, alongside six rebounds and three assists, but the modest Herro pointed to the influence of Butler as a telling factor in his rapid rise.

"Jimmy, ever since I got here, he's been like a big brother to me and he's shined light on me. He's taught me a lot of things," Herro said.

"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. Without Jimmy, I probably wouldn't be doing this as a rookie.

"We have a great group of guys in the locker room and everybody wants to win. I know my role. It's not to score 30, whatever I had tonight. It's not to do that every night.

"Some nights it may require me to step up like tonight and make some shots. But I know in the fourth quarter, we're going to get the ball to Jimmy; we're going to get the ball to Goran [Dragic].

"Those are our guys. We are going to run to them and they are going it make the most plays for us and they are going to win us games most of the time."

Although Herro remains deferential to such senior figures, he gives himself plenty of credit too for making it at the highest level, having been told repeatedly he lacked what it would take.

"I'm just going to bet on myself. I've been doing that my whole life," he said. "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."

Reflecting on his time in Kentucky, he explained: "I think someone said my wingspan was too short. They say everything, but whatever they say, it's whatever."

Herro contested the suggestion he was the leading player in Wednesday night's game, pointing to the likes of Butler, Dragic and Bam Adebayo, and predicted "a dogfight" in Game 5 on Friday night.

Butler, who had 24 points and nine rebounds, continues to be impressed by his young team-mate.

"Not too many people get an opportunity to make it this far in the playoffs and to be in a game like this. But for him, it's another day at the office," Butler said.

"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."