This one hurt more than most.
On paper it was just a 120-115 overtime road loss to an underachieving, yet supremely talented, Pelicans team. But it was so much more. This was a complete and utter disaster for a Celtics team still wallowing in inconsistency.
For three quarters, life couldn't have been much better for the Celtics.
Brad Stevens' team had built up its lead to 24 points with just more than six minutes left in the third, with contributions coming from all over the box score -- on the offensive and defensive end of things.
Jayson Tatum and Jaylen Brown were doing their things. Kemba Walker, while struggling from the outside (5-for-21 from the field), was showing the kind of burst the Celtics have been starving for.
Robert Williams was flying all over the place, reaching heights on lobs many thought were unimaginable. Rookies Payton Pritchard and Aaron Nesmith had given the Celtics solid production off the bench.
And then there was Tristan Thompson.
The veteran center had given the Celtics what so many had hoped he would when signing that two-year deal, providing a nice offensive complement on the inside. But more importantly, serving as the Celts' answer to New Orleans second-year power forward Zion Williamson (28 points).
Life was good. A lot of question marks had suddenly become exclamation points.
But then that other version of the Celtics arrived, the inconsistent one that couldn't find any other answers outside Brown and Tatum. It was also that squad that led the other team's star do whatever he wanted -- in this case Williamson.
The former Duke star and his team flipped a switch against the Celts in the fourth quarter, culminating in Williamson's go-ahead layup over Thompson with just more than six seconds to go.
Fortunately for the Celtics, they could turn to Tatum to save the day in regulation, with the forward's drive to the hoop culminating in a game-tying runner with under one second to go, sending things to overtime.
But New Orleans' momentum didn't stop at the end of regulation, with Brandon Ingram (33 points) giving the hosts the lead for good thanks to a three-pointer with 33 seconds remaining.
The Celtics had one last chance to tie it up with 8.3 seconds remaining in overtime. But Tatum missed both free throws after being fouled on an inbound pass, ending a dismal evening for Stevens' team and sealing the biggest comeback in Pelicans' history.