BOSTON — As Derrick White went to the line for his 25th and 26th points of the night, the TD Garden crowd showered the Celtics guard in the "MVP" chants usually reserved for teammate Jayson Tatum.

"So, that's what it feels like?" White asked Tatum after their 119-106 win over the Atlanta Hawks.

"Yeah," said Tatum, whose Celtics took a 2-0 lead in their first-round playoff series. "I guess so."

The Boston crowd affirmed what White rediscovered in his first full season with the Celtics: He belongs.

White's basketball journey is unlike Tatum's or most anyone in the NBA. Barely 6 feet, 155 pounds as a high school senior, he did not receive any scholarship offers, settling for a stipend from Division II University of Colorado Colorado Springs. It took three years and a late growth spurt to earn a transfer to the DI campus in Boulder. Weeks before the 2017 draft combine, White seized one of a handful of invites from a showcase for graduating seniors, and there the San Antonio Spurs saw enough to make him their 29th overall pick.

Behind Dejounte Murray, Patty Mills and Tony Parker on the depth chart, White spent much of his rookie year in the G League. Murray's torn ACL, Parker's exit and Mills' success as a sparkplug off the bench left a vacancy in the 2018-19 starting lineup, and Spurs coach Gregg Popovich rewarded White's improvement.

"Derrick's a really special case of someone over time figuring out that he belongs," Popovich said when his Spurs made their annual visit to Boston last month. "Most NBA players don't know how to play. He did, and he added skill development on top of that. ... He just got better and better because he put so much time in, and then it was just a matter of convincing him that he did belong so that his confidence would grow."

That scouting report accompanied White in his trade to the Celtics at the 2022 deadline. He had moments on Boston's run to the Finals, including 21 points in a Game 1 win against the Golden State Warriors, but he disappeared down the stretch of that series. White's son was born during the Eastern Conference finals, and he had been thrust into a new role on and off the court. How we belonged was his question again.

That changed over the course of this season, White's first full with the Celtics, as Tatum and Jaylen Brown encouraged their USA Basketball teammate to make defenses pay for double-teaming Boston's All-Stars.

Brown would remind White during timeouts, "C'mon, D, be aggressive. Do what you do."

"We're just so much more of a dynamic team when D-White is asserting himself and being aggressive," Tatum said after scoring a team-high 29 points in Tuesday's win. "We've talked about him being too passive and looking for guys too much. He's like too good of a guy. These last few games, being aggressive, making the right play, attacking the rim, not necessarily waiting just makes us that much better of a team."

"It's cool to hear that from those guys," said White, "and they empower me to go out and play my game."

That game has been a revelation for the Celtics this season. White started in the backcourt alongside Marcus Smart when Boston opted for small-ball in the injury absence of Robert Williams III, and his performance has left Celtics coach Joe Mazzulla no other choice but to play him as often as possible.

White's 65.6% shooting at the rim and 38.1% clip from 3-point range are easily the most efficient of his career, and he deserves his first selection to an All-Defensive team. His +9.3 on/off rating is nearly twice the mark of the next-best member of the Celtics, whose +6.7 net rating led the NBA during the regular season.

"He's just more confident, more comfortable, has more of an identity," said Mazzulla. "Any time you join a team late, especially a team that's been together a long time with high expectations, you're just trying to figure out how and where you can have an impact. Stuff like that just comes with time, and now he has a clear identity. He can handle for us, he can play off the ball, and he's really gotten used to our defensive schemes as far as our switching and how we match up and what the coverages are based on those matchups. He has an effect off-ball, on-ball, at the rim at times, so I just think he has a clear-cut identity."

In two games against the Hawks, White's 50 points are second to Tatum. Atlanta's Trae Young heard the footsteps of White's five blocks in the third quarter on Tuesday, short-arming two floaters as Boston pushed its lead to 20. White has been the best guard in a series that includes Smart (a Defensive Player of the Year), Malcolm Brogdon (a Sixth Man of the Year finalist), Young (a two-time All-Star) and Murray (a 2022 All-Star who recently lamented, "They really had me competing against Derrick White" in San Antonio).

"Last year was kind of a whirlwind ever since I got traded for a lot of reasons, but this year, from the first day, I just felt comfortable," said White, who turns 29 in July. "I'm just trying to get better each and every day, and the team is doing a great job of empowering me and helping me out throughout the whole ride."

He may not be the MVP, but on arguably the NBA's deepest team, White has been the third-best player behind Tatum and Brown, and the Celtics know fully well that could tip the Finals in their favor this year.

"We need much more of that from D-White," said Brown. "I need him to keep that up."

"S***, I'm happy for him," added Tatum. "He's been playing his ass off these last two games. He's obviously a big, big reason we won these last two games. We need him to continue to play at this level, and he can."

Yup, Derrick White belongs.