Kevin Garnett thinks LeBron James should mind his own business. After James criticized Garnett Paul Pierce and Jason Terry Wednesday for leaving Boston a year after criticizing former teammate Ray Allen for signing with the Heat as a free agent Garnett took the opportunity to shoot back at James. “Tell LeBron to worry about Miami” Garnett said after the Nets beat the Heat 86-62 in front of a sellout crowd of 17732 at Barclays Center Thursday night. “He has nothing to do with Celtic business.” As for Pierce when the question was posed to him he answered with one of his own: “I left Boston?” Pierce has a point as Allen chose to leave Miami as a free agent while Pierce Garnett and Terry were traded away as Boston opted to blow things up and start over. Nevertheless the back-and-forth between James Garnett and Pierce was only more proof — none of it necessary — the acquisition of the two Celtics icons along with other moves over the summer has helped earn the Nets a level of respect from the defending champions they never had at any point last season. It has also clearly transferred over the venom that existed between Boston and Miami to Brooklyn. “We’re trying to install that here” Pierce said. “They’ve taken what we’ve tried to accomplish the last couple years in Boston. We’re here in Brooklyn now and it’s the same type of attitude. “They’re the champs they’ve got what we want and we have to go through them to get it. We’ve got to just help everybody understand that it’s not going to be easy and we’ve got to win.” Once the game got underway following Jason Kidd’s pregame jersey retirement ceremony it often had the feel of a regular-season contest — particularly whenever James and Pierce were on the floor at the same time. Early in the first quarter James took it to his longtime rival in the post hitting a difficult turnaround jumper over Pierce’s outstretched arm.