"I knew Posey was going to sit on my arm, so I just had to back him up and try to shoot it," Bryant explained. "I knew it was going to be a tough shot because I had Posey draped all over me, so I just needed to focus on the basket and try to put it in."
Derek Fisher hit four 3-pointers and also finished with 20. He had 18 through three quarters, leading what had been a dominant effort by Los Angeles, which never trailed.
The Lakers led by as much as 23 before nervously holding on against a team that is expected to be one of their chief rivals for Western Conference supremacy.
Chris Paul led New Orleans (4-3) with 30 points and 13 assists, scoring 16 points in the fourth quarter.
The Lakers appeared to have the game in hand after Andrew Bynum's 8-foot turnaround jumper increased their lead to 79-63 with less than six minutes to go.
But Paul scored 11 points and assisted on three other baskets during a stirring surge that pulled New Orleans to 83-80 on Paul's floater off the glass with 1:33 left.
The fans were on their feet, urging on the defense, which appeared to be on the verge of getting another stop when Bryant's difficult 3-pointer as the shot clock wound down hit the back rim and dropped straight through.
"I'm never surprised to see him do anything," Fisher said. "He's one of those rare guys in the history of the game that I think can actually make the ball go in."
Trail Blazers 104, Heat 96 - Greg Oden, the No. 1 pick in the 2007 draft, returned to visiting Portland's lineup, scoring 3 points and grabbing two rebounds in 16 minutes off the bench to help his team beat Miami.
The hard-luck center missed all of last season following knee surgery and only managed to play 13 minutes after spraining his right foot against the Lakers in his long-awaited debut last month. He sat out six games with the injury.
But another Portland rookie stole the show against the Heat. Rudy Fernandez scored 25 points, including a clutch, spinning jumper as the shot clock expired with 44.9 seconds left.
Rockets 94, Suns 82 - Tracy McGrady scored 22 of his 27 points in the second half, and visiting Houston beat Phoenix in a game that featured a skirmish that drew two ejections and seven technical fouls.
