The NBA Cup is beyond dumb. If you want to rip off European soccer at least have a format that doesn't eliminate the best team in the NBA from the competition for losing one group game. 3-1 in group play and eliminated on point differential is just stupid. Or if you want to incorporate point differential then you need to have all teams playing at same time on final night of group play. Come up with something better. I'd even take no group play at all. Seed the NBA Cup like an NCAA tournament and start it halfway thru the season based on current standings. I don't know.
Celtics are out because they lost to Atlanta without their best player. they probably could have tried to run up the score in a different game, but I don't think they even remotely cared.