BOSTON -- Robert Williams was at his game-altering best in the Celtics' 2023 playoff opener.
The high-energy big man only tallied 12 points Saturday afternoon at TD Garden but did so on a perfect 6-of-6 shooting while stuffing the stat sheet with eight rebounds, two assists, one steal and one block in Boston's 112-99 win over the Atlanta Hawks.
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Williams' performance marked the third postseason game of his career in which he scored 10-plus points on 100 percent shooting -- tying a Celtics franchise record.
Ed Pinckney is the only other player with three such postseason games with the Celtics, during the 1990 and 1991 playoffs.
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Williams' previous two "perfect games" came during the 2020 postseason -- both in wins over the Toronto Raptors in the second round -- but this might have been his most impactful of the three. The Celtics consistently found Williams at the rim for highlight-reel dunks, and he kept the ball moving with quick reads on outside touches.
On the other end, Williams played his usual dynamic defense, forcing the Hawks to settle for outside shots and erasing those that came near the paint.
"It’s just his presence at the rim on both ends of the floor," Celtics head coach Joe Mazzulla said after the game.
"I thought he did a good job of protecting us in the paint, especially in the first half. I though he did a great job keeping his spacing and creating screen angles for our guys. So when we have that vertical threat it really helps us with rim protection as well."
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Health has always been an issue for Williams, who only played in 35 games this season due to various injuries. But when he's 100 percent and impacting winning at both ends like he did Saturday night, the Celtics are very hard to beat.
Williams will aim for an encore performance Tuesday night in Game 2 at TD Garden, which tips off at 7 p.m. ET with NBC Sports Boston's coverage beginning at 6 p.m.