The Boston Celtics ran through a gauntlet of an Eastern Conference playoffs draw, defeating the Kevin Durant and Kyrie Irving-led Brooklyn Nets in the first round, dispatching the defending champion Milwaukee Bucks and then squeaking out a win over the formidable Miami Heat in seven games to advance to the NBA Finals. Led by Jayson Tatum and Jaylen Brown, as well as a strong core behind them, the Celtics have officially arrived as a legitimate contender. During an interview with Sirius XM Radio, Boston guard Marcus Smart revealed this key difference that he’s seen in Tatum and Brown.

Smart said that Tatum and Brown’s “selflessness” has been the biggest difference for the Celtics this season. It’s something that Smart- and others– have criticized the two young stars for in the past.

Live and breathe the NBA?

🚨 Get viral NBA graphics, memes, rumors and trending news delivered right to your inbox with the Clutch Newsletter.

It was clear that Tatum and Brown could create offense for themselves. The question was, could they do it for their teammates? Smart believes they have, with the two maturing into such a role.

The Defensive Player of the Year implied that Tatum and Brown too often were trying to get theirs early on in their career. The numbers certainly support that sentiment, as both Celtics star’s assist totals have increased by the year.

They look the part of more mature players out on the court. The Celtics are better for it too, as they are in the NBA Finals for the first time since the 2009-10 season.