With star defender Marcus Smart as a vocal leader plus scoring spark from Jaylen Brown and Jayson Tatum, the Boston Celtics have reached their first NBA Finals since 2010.

The trio of 20-something stars united to lift the Celtics from a 23-25 start into a best-of-seven showdown for the crown against Golden State that starts Thursday.

"We all just got comfortable with each other through experience," Brown said Wednesday. "We've been playing together so long. So you learn each other's tendencies and traits and how to speak to each other and how to basically just be a better teammate."

Brown, 25, was taken third overall by Boston in the 2016 NBA Draft while Tatum, 24, was picked third in the 2017 draft and guard Smart, 28, was selected sixth in the 2014 draft.

Together they advanced as far as the Eastern Conference finals three times in four seasons before finally reaching the NBA Finals this season, Smart winning the NBA Defensive Player of the Year award and serving as an outspoken leader.

"Over time, you learn, you make mistakes, you argue, you fuss, you fight," Brown said. "But once you've been together for so long with a core group, and you've been in the Celtics organization as long as Smart has been, you find different ways to be an example."

Smart notably called out Tatum and Brown early in the season, but his example has helped the two top scorers to find their own voice in the locker room as well as showing off their skills on the court.

"Marcus is emotional as a player in the things he says and the way he plays and wears it on his sleeve," Celtics coach Ime Udoka said.

"Nothing said publicly had not been said privately. Although it may rub people wrong because it was said publicly, that was something we were working on behind the scenes every day.

"Marcus, as well as the others, their leadership and being vocal has been invaluable to the group. Jayson and Jaylen have grown in that area and do it their own way. That mix of leadership and different styles benefits our team."

Smart recalled teammates supporting him after his mother's death and how players lean on each other for support.

"We have a special bond outside of basketball and to be able to go to war with those guys makes that bond even stronger," Smart said.

"I just wanted to let them know, we can express it here. We can talk about it. Whatever we need. We are brothers."

- Brown faith lifts Tatum -

Tatum wondered if he was the player the Celtics needed, but discovered he was with a little help from his friends.

"There have been times where I questioned, am I the right person to kind of lead a group like this," he said.

"We lean on each other in those moments. As hard as it can be in those times, you've got to come closer together."

Brown's faith was strong when Tatum's was lacking.

"I haven't done too much questioning about anything," Brown said. "I didn't have any time to question what was in front of me because my belief was so strong."

Tatum, who helped the US Olympic team win gold last year in Tokyo, bonded with Brown when some felt the team wasn't big enough for them both.

"Just two young, extremely competitive guys that just really want to win at all costs," Tatum said of himself and Brown. "That made us closer in the sense of we just wanted to figure it out."