The NBA Summer League is underway and the rookies for next season are already impressing their teams.Jayson Tatum's Boston Celtics went up against Markelle Fultz's Philadelphia 76ers, and both players indicated that they have the potential to have big years for their new teams in the 2017-18 season.The Celtics won the close game 89-88, and it was Tatum that provided the game-winning shot to give Boston the victory.The Duke product pulled off a 17-footer with around five seconds left in the game to give the Celtics the lead by one. This was enough to see his team across the line to give his team the win on his summer league debut.

Tatum also had a pretty awesome dunk in the second quarter of the game in what was a very impressive debut for his new team.

The 19-year-old finished the game with 21 points, seven rebounds, five steals, and three assists for the Celtics. Fultz had a good outing for the Sixers with 17 points, but this was Tatum's night.

Tatum praised Fultz for his performances on the court after the game, noting how both of them are finally living their dream of playing in the NBA.

Tatum said, according to csnne.com: “Me and Markelle have known each other a long time from high school, played against each other, all-star games. We finally reached our dream and I’m pretty sure we’ll compete against each other for a long time.”

Celtics assistant coach Jerome Allen who is coaching the team’s summer league squad in Salt Lake City was impressed with Tatum, as he said: “He has this old soul … he doesn’t get rattled. Just kind of plays at his pace, like he’s been here before, at 19.”

Tatum was pleased the coaching staff had confidence in him to take the game-winning shot, as it provided him a valuable learning experience. He said: “It put a lot of pressure on me, to take the shot. But that’s what summer league is for; to learn some things, if I would have made it or miss it.”