LAS VEGAS — Celtics forward Jayson Tatum admitted he didn’t come close to meeting lofty expectations last season — both those he placed upon himself and those from the outside world — but he’s eager to assert himself as one of the NBA’s elite this season.

"I want to be one of the best,” Tatum said after Team USA’s practice Tuesday on the campus of UNLV. "There’s a lot of challenges that come with that. I’m excited.”

Tatum noted last week that he wanted to make a “bigger jump” this season, hinting that he didn’t play to his own expectations last year. Pressed on the topic Tuesday, Tatum admitted he came away wanting more, especially in a season that frustrated many on Boston’s roster.

"Man, it’s hard to pinpoint one thing from last season,” said Tatum. "All my stats were better, I did better, just not the jump that I expected — and the rest of the world expected. Which, I should have known with the team, the dynamics — we had so many guys, so many talented people trying to win a championship and everybody had to sacrifice and step back a little bit. It didn’t work.

"Last year is behind us. Everybody is kinda tired of talking about last season. We got a new team, new guys, so we’re just trying to move on, get ready for next season.”

Tatum, 21, believes a bigger leap starts with him carrying himself like an NBA superstar.

"Be more assertive, be more vocal than I was in my first two years,” said Tatum. "I was really the new guy so I didn’t say too much. But now I’ve earned the respect of the coaches and teammates and people around the league so just being able to talk a little bit more.”

Tatum’s 2018-19 season has been heavily dissected. While he owned the best on-court net rating on the Celtics, among high-volume players — higher even than All-Star Kyrie Irving and Al Horford — Tatum didn’t make the statistical leaps that many believed were coming after his loud 2018 postseason. Expectations might have been out of whack from the moment Tatum dunked on LeBron James in Game 7 of the Eastern Conference finals but Tatum still expected more from himself.

Teammate Jaylen Brown said that Tatum might be a little too hard on himself. But he understands Tatum’s desire to show that these young Celtics haven’t come close to their potentials.

"I think he had a solid year. He’s probably his toughest critic,” said Brown. "I didn’t think he had as bad a year as he probably thought he did. I think he still produced, I think he still got to show people what he can do.

"I’m sure, in his eyes, he has a lot more he wants to show the world, as do I. So I can feel him in that regard. He had a solid year, it wasn’t as bad as people tried to make it out to be.”

If Tatum had a so-called down year last season, it hasn’t seemingly affected the way he’s viewed around the NBA. Tatum signed on with Michael Jordan’s “Jumpman” brand this summer and, during a promotional event in Paris, he might have greased the skids for Kemba Walker’s decision to join the Celtics.

Walker said Tuesday that he talked with Tatum for nearly an hour in Paris and it might have been the final nudge Walker needed to later commit to Boston. Walker has glowed about his new teammates, particularly the combo of Tatum and Brown, and the opportunity to play alongside a talented young duo.

"Those dudes are so talented, it’s unbelievable,” said Walker. "I competed against those guys, what, four times a year? Might catch a few games here or there. End of the day, you don’t see them every day. You know what I mean? For me, to be here and see those guys, and the way they compete and how much passion and love they have for the game, the intensity they have for the game, that’s special to me.”

Tatum noted how he and Brown have pushed each other throughout their young NBA careers and continue to do such. The duo played “King of the Court,” a rotating 1-on-1 game, with Team USA teammates after practice Monday and Tatum had some dominating stretches. He joked he’s got the upper hand on Brown in their career series against one another.

Both, overall, they’re both pulling on the same rope. Tatum and Brown are both eager to show that last year wasn’t a reflection of what they will someday be.

"This year, I look at it as a new canvas,” said Brown. “We’re artists, and it’s time to paint.”

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