While it's not always the most exciting product, NBA Summer League gives us a chance to see rookies with high expectations play against NBA athletes for the first time.

Monday was our first marquee matchup between rookies of 2017, as the 76ers and No. 1 overall pick Markelle Fultz took on the Celtics and No. 3 pick Jayson Tatum in the Utah Summer League. Fultz and Tatum are considered the two of the most NBA-ready rookies this season, and making the matchup even more exciting was the fact that the two were basically traded for each other (the Celtics traded the No. 1 pick to the Sixers for No. 3).

It was about as competitive as Summer League games get, with the Celtics pulling away for an 89-88 win on a go-ahead jumper by Tatum with 5.7 seconds left.

Fultz had a chance to answer but missed a difficult reverse layup just before time expired. Tatum finished with 21 points, seven rebounds, three assists and five steals in 34 minutes, while Fultz put up 17 points, two rebounds, one assist and three blocks for the Sixers.

Here are a few takeaways from our first look at the two explosive rookies.

Tatum is silky smooth

From the opening whistle Tatum played with a level of poise uncharacteristic of a 19-year-old. Not considered to be an explosive athlete, Tatum seemed to get where he wanted by using his quickness, length and footwork. He showcased his ability to finish in traffic by throwing down this ferocious dunk.

Then in the second half he showed off his old man game with a low-to-the-ground step-through, almost like a late-career Kobe Bryant. Overall, Tatum displayed all the offensive versatility he was billed to have, and then some. Sure, it's the Summer League, but draining a game-winner in your first professional game certainly can't be a bad thing. He's also not pretending that he has all the answers, admitting after the game that he has a long way to go.

"It was a lot tougher than I thought," he said.

Fultz shines on both ends

Everyone was excited to see the No. 1 pick play, and Fultz knew it. He started off the game by hitting his first professional shot, and that gave him the confidence (as if he needed any more) to put his full offensive arsenal on display. He even drew the praise of Kevin Durant, who gave a highly scientific basketball assessment.

The rookie continued to showed his "poop emoji" and "hesi pull-up jimbo" throughout the game, hitting two of his five 3-point attempts, but it was his defensive effort that stood out. Fultz had three blocks from the point guard position, including this erasure on Kadeem Allen's layup attempt.

Fultz had some defensive question marks heading into the draft, so seeing him getting after it on the defensive end in his first game is a great sign for the Sixers. The Washington product shot 6 of 16 from the floor and had four turnovers, but that kind of inefficiency is to be expected. Overall it was an "A" outing for the newest iteration of The Process.

Hey, don't forget about Jaylen Brown

The Celtics have cornered the market on promising young wings with an unnecessary letter "Y" in their first name. Brown proved that he is well beyond summer league, putting up an easy 29 points and 13 rebounds in 30 minutes. He was the pinnacle of efficiency, shooting 10 of 16 from the field including 3 of 4 on 3-pointers, as he looked like a man among boys.

Because he only played 17 minutes per game for Boston last season, people tend to forget that Brown was the No. 3 pick in the draft last year. At just 20 years old, games like this show how high his ceiling really is. As much as Celtics fans clamored for a Paul George trade, a wing combo of Tatum and Brown is a pretty nice consolation prize moving forward.

Bolden the Block Machine

Fultz wasn't the only rookie to put on a show for the Sixers. Second-round pick Jonah Bolden proved that he can make an immediate impact on the defensive end, blocking four shots in 22 minutes and embarrassing people along the way.

Bolden also did damage on the offensive end, scoring nine points, including a 3-pointer and a vicious putback slam.

A 21-year-old who played last season in Serbia after two years at UCLA, Bolden showed glimpses of being an elite rim protector who could develop into a lob finisher who can also stretch out to 3-point range. While their top picks (Fultz, Ben Simmons, Joel Embiid) get the headlines, it's players like Bolden who could end up developing into the pieces the Sixers need to emerge as a real threat in the East one day.