Robert Williams has officially arrived. Or maybe he was already here. It's hard to tell with a player nicknamed "Time Lord," an appropriate moniker for reasons beyond his youthful tardiness. In a single game, Williams manages to look like a rookie, a veteran and a superstar all at once, mixing mind-blowing defensive brilliance and athleticism on one play with questionable mistakes on the next. Time is a flat circle for Williams, and that's a concept that the Boston Celtics have never been particularly comfortable with. 

Williams has started only 16 games in his NBA career. Prior to this season, he'd never even played 30 minutes in a game. Celtics coach Brad Stevens has tended to lean on more reliable veterans like Daniel Theis and Tristan Thompson, but as an enormous underdog against the championship-favorite Brooklyn Nets, he had no choice but to make the upside play. Williams played nearly half of Saturday's Game 1 against Brooklyn -- a 104-93 loss -- despite a nagging turf toe injury, and boy, did he deliver. 

Williams came only one block and one rebound short of becoming the third player in NBA history to record a postseason triple-double involving blocks. The Celtics limited the Nets -- who have perhaps the best collection of offensive talent in NBA history -- to only 93.2 points per 100 possessions with Williams on the floor in Game 1. When anyone else was at center, Brooklyn scored 126 points per 100 possessions. 

It was an absolute masterclass from Williams in meshing superior athleticism with fundamentally sound defense. This play came straight out of the LeBron James playbook. Williams knows he has help at the basket, so rather than risk fouling Kyrie Irving on the perimeter, he lets Irving get past him knowing that his help will give him enough time to recover. He does, and he swats Irving's layup attempt out of bounds: 

That recovery speed was on full display against the Nets, and it wasn't just useful in straight-line drives. This time, he switches onto Joe Harris off a screen, successfully deters the first drive, scares Harris out of the 3-pointer and then blocks him on the second attack:

Harris wouldn't dare attempt a shot over Williams. Let's see how James Harden was rewarded for his boldness: 

To reiterate, this is James Harden we're talking about here. He hunts big men for sport off switches. He's largely responsible for ruining Rudy Gobert's playoff reputation, and on this play, he uses his signature move, the stepback, which he developed largely as a counter to elite athletes. You're not supposed to be able to block the Harden stepback. That's why he's stepping back in the first place. But Williams did it. 

That's what makes him so special on defense. He's such a gifted athlete the normal rules of defense don't need to apply to him. This is what "drop" coverage looks like for Williams: He still comes out to the 3-point line and manages to force Harden into a short-roll pass to Nicolas Claxton. Most centers have to make a choice in this situation: blitz Harden at the level of the screen to try to force that pass, or drop far enough to take away Claxton's shot. Williams effectively does both at the same time. It leads to yet another block: 

This one is an Anthony Davis special, and again involves Williams effectively defending two players at once. He's nominally on Jeff Green in the dunker's spot, but rotates to the perfect patch of land on the court: close enough to Irving to deny the shot, but close enough to Green to deny the pass. Irving tries it anyway, and amazingly, Williams' reflexes are so fast that he knocks it away for the steal on his second swipe. There isn't much distance here. Williams shouldn't have time for two swipes: 

Those reflexes make him a lethal shot-blocker. Zion Williamson has the best second jump in the NBA, but Williams is not far behind: 

If you're looking for a hole in his defense, you'll see it on that play. He didn't box out, and that's what generated the offensive rebound opportunity that led to the block in the first place. That happened multiple times against Brooklyn: 

This is poor situational awareness, and that has been a flaw of Williams' throughout his career. But the mistakes are becoming fewer and further between as he ages into the next stage of his career, and now, the onus is on Boston to decide whether or not it trusts him to erase those mistakes entirely. 

Williams becomes extension eligible after the season, and odds are, those negotiations are going to be difficult. The Celtics haven't played Williams enough to know for certain whether or not he can handle a starter's workload. Williams and his agent will likely try to negotiate on the potential he flashes in games like this one. Boston can't make commitments like that willy-nilly. Kemba Walker is on a max deal. Jaylen Brown is close, and Jayson Tatum's new contract kicks in next season. The Celtics are going to be a tax team for at least the next two years, and that's before you factor in a possible new deal for Evan Fournier

The Celtics kicked the tires on at least one more prominent center at the deadline in Nikola Vucevic. There's an inherent logic to that ambition. Boston has a max salary guard and two superstar wings. A center is the next logical core piece if the Celtics look outside of their building to find one. 

But if there's any advantage to playing out this likely first-round sweep against a far superior Nets team, it's that the Celtics now have the chance to evaluate Williams against playoff-caliber competition in a steadier role. If he can be their center of the future, he'll have the chance to prove it against Brooklyn. He passed his first test with flying colors. If Game 1 is any indication, the future is now for Boston's Time Lord.