Boston Celtics small forward Jayson Tatum says playing for Team USA this summer helped build his confidence as a basketball player.

By all accounts, Tatum has been one of the most impressive players in Celtics training camp thus far. In Boston's preseason opener against the Charlotte Hornets, Tatum showed off his growth by pouring in 20 points in 23 minutes in the Celtics' 107-106 win.

Tatum says he's going to get more mature year after year and that his Team USA experience was big for him:

“Playing with USA Basketball this summer has a lot to do with it,” Tatum said, via MassLive.com. “Just getting that early work in this summer, it being super-competitive. We went after it every day in practice, some of the best young players in the league. That was big.

“It's my third year. I feel like everybody gets more confident and better and more relaxed and mature year after year. I mean, I don’t want to go backwards.”

With All-Stars Kyrie Irving and Al Horford gone, the Celtics are going to be expecting a lot more from Jayson Tatum this season, and the talented swingman is ready for a bigger role in Boston.

Last season, Tatum averaged 15.7 points, 6.0 rebounds and 2.1 assists while shooting 45.0 percent from the field, 37.3 percent from beyond the arc and 85.5 percent from the free-throw line.