I consider the Nets a level higher than Boston given a healthy Kyrie Irving and Kevin Durant while Boston no longer has Gordon Hayward and Kemba Walker is out. Early money in the marketplace agrees as the Nets have been pushed up to this point spread range. It's justified. 
The Nets are the better team and they want to make an early statement in proof of that. This is their chance being on national TV on Christmas Day. The Nets haven't played on Christmas Day since 2013. This also is Irving's first regular season game against his former team. 
Brooklyn built a 38-point lead against Golden State in its opener this past Tuesday, winning 125-99. The takeaways from that game were not just Irving and Durant looking good, but that the Nets had 28 fast-break points, seven blocks and 11 steals. 
The Celtics pulled off a dramatic, 122-121, home win against the defending Eastern Conference champion Bucks this past Wednesday. I see the Nets not just as the more talented team, but also the more motivated. They also have the deeper bench.