LAS VEGAS – In the 6 minutes, 45 seconds he played in his first NBA game, Robert Williams was gaining comfort.
He followed a two-handed dunk with a midrange jumper. He had two rebounds. The jitters were going away.
Then he bumped knees with a Philadelphia player and his night was over.
The Celtics’ first-round pick had an abbreviated debut in Boston’s 95-89 summer league win over the 76ers, leaving late in the first half with a sore left knee.
Williams said that he had been suffering from tendinitis in that knee and the bump “hit me in the exact same spot.”
The relief was the injury didn’t appear to be serious, but it’s uncertain whether Williams will play Saturday night against Denver.
After a couple of embarrassing incidents since being drafted, Williams was just glad to be on the floor, even though it lasted less than seven minutes.
“It’s definitely frustrating, my first NBA game,” he said. “So obviously I wanted to be out there with my teammates, out there with my guys. But it’s a long road ahead of me and the body comes first.”
Williams did not start the summer league opener, perhaps as a punishment for being a no-show at the opening practice after a missed flight. He checked into the game in the first period and looked comfortable as the game progressed.
With Williams being the lone 2018 draft pick on the roster, his progress this summer is the team’s highest priority.
“We’re excited about him, obviously,” summer league coach Jay Larranaga said. “He’s been very diligent in trying to pick up our system.”
The past week has been a crash course for Williams, who joined his teammates Monday and has been learning since, especially from older teammates Semi Ojeleye and Guerschon Yabusele.
“Just absorb everything, the good and the bad, know what to do and what not to do,” Williams said when asked of his experience the past week. “Follow the right people. I’m led by good vets, Al Horford, [Aron] Baynes, so just trying to learn the right path to have a successful career.”
Although it was summer league and Williams will play in bigger games, it was still his first organized pro game. He relished the experience.
“Definitely faster, stronger, bigger, it’s the NBA,” he said. “But I’m built for the NBA in my perspective. It’s exciting just to have that brand on you, just to have that logo knowing that you’re in the NBA. But it’s definitely more to come, it’s just summer league. There’s more grind left.”
Williams said he was quickly introduced to NBA physicality when strongman Baynes guarded him in the post, put his hand on Williams’s waist and basically moved him around like a child.
“It was definitely a wake-up call,” Williams said. “I never knew a guy’s hand could be so strong, just one hand. He was showing me the techniques.”
What has perhaps overwhelmed Williams is the NBA’s attention to detail, not only setting hard screens, but at the right angle and being able to free yourself from the screen to roll to the basket.
“It’s way more detail from practice all the way to the game,” he said. “Doing things the right way and 100 percent, not just 100 percent and messing up everything.”
In the game, the Celtics led most of the way before the 76ers went on a 33-17 second-half run behind the stellar 3-point shooting from Furkan Korkmaz, who had eight 3s and 40 points.
Ojeleye and Yabusele (16 points each) helped the Celtics rally in the final four minutes along with two 3-point plays from Rhode Island product Hassan Martin (8 points).