He only felt like one when he returned to his locker and sat next to the pink "Little Mermaid" suitcase his teammates have made him cart around all season.
"Until they stop having me come in with doughnuts and carrying that [suitcase], I'm still a rookie," Collison said. "I like being a rookie. You learn a lot. ... I can't see why anybody doesn't like being a rookie."
Easy for him to say after he scored 13 of his 25 points in the final period to lift New Orleans to a 93-85 comeback win Wednesday night.
Splitting defenders on the dribble, tossing in floaters over crowds of defenders in the lane and draining mid-range jumpers, the Hornets' first-round draft pick tormented veteran Boston down the stretch. At one point, he scored 11 straight points to ensure his team protected a single-digit lead to the end.
"I didn't want this game to get away from us," Collison said. "I just wanted to make sure we had enough pressure on them where we had a lot of comfort zone where we could come out with the win."
That's precisely how Hornets coach Jeff Bower wants Collison to think, especially now that All-Star point guard Chris Paul is sidelined for a month or so after having surgery to repair a torn meniscus in his left knee.
"We don't treat him like a rookie point guard who's filling in," Bower said. "We treat him like the point guard of our team who has a responsibility to his teammates ... and he doesn't back down from that."
Peja Stojakovic scored 20 for New Orleans and Morris Peterson had 16 points and 10 rebounds for his first double-double in more than two seasons. David West added 15 points to help the Hornets go into the All-Star break with two wins in their last three games.
Paul Pierce scored 15 points for the Celtics, who played without starting guard Ray Allen (back spasms) in their second straight loss. Marquis Daniels added 14 points for Boston, which missed 11 free throws -- clanking 10 of 13 in the second half -- while squandering a 12-point halftime lead.
"It's tough to win games when you turn the ball over and miss free throws," Celtics coach Doc Rivers said.
The teams combined for 47 turnovers, with the Hornets committing 24, including a franchise-high 10 by Collison.
"That's rookie mistakes right there," Collison said. "That's something I'm going to be looking at the film to assess."
Trailing for much of the first half, New Orleans seized the momentum in the third quarter by hitting six 3-pointers, including three by Stojakovic and two by Peterson.
The Hornets surged into the lead with an 11-0 run on Stojakovic's fourth 3 of the game, Peterson's three-point play on a tough transition layup, Collison's 3 and Stojakovic's jumper, which made it 72-65.
"Our defense was horrible in the third quarter," Rivers said.
The Celtics shot 5 of 19 from the field and only 2 of 9 from the foul line during the quarter.
Daniels briefly got Boston's offense rolling again, scoring three baskets during an 8-2 run that pulled the Celtics to 76-75 early in the fourth quarter.
However, New Orleans didn't wilt as it did two nights earlier in Orlando, when the Magic overcame a 17-point deficit.
Collison hit a double-pump runner and followed it with a driving floater through a crowd as he was fouled. He added a jumper and then split Eddie House and Glen Davis on the dribble for another layup to make it 85-78.
Collison wound up missing a dubious triple-double by one assist.
Pierce committed eight turnovers and scored only two points in the second half. Kevin Garnett had seven points and seven rebounds in 26:29 and did not score in the second half, missing an open but rushed fastbreak layup in the final minute when Boston trailed by six.
"Our starters struggled," Rivers said. "Kevin struggled in the second half and Paul forced too much due to the struggling of the team."
Davis, a Baton Rouge native and avid Saints fan, said he was able to watch the NFL club's championship parade with several Celtics teammates from in front of their Canal Street hotel Tuesday night. ... The Hornets played their final game of four in their purple, green and gold "Mardi Gras" uniforms, meaning the Celtics had to wear home whites. ... The Hornets are 3-4 since Chris Paul went out with his knee injury. ... Several Saints players made appearances at the game to raucous applause, including safety Darren Sharper, and ends Will Smith and Bobby McCray.
LeBron James called Tuesday for people to lend their hands in their communities to make the United States "as great as we can be as a nation."
Yes, the U.S. men's juggernaut has sputtered into the quarterfinals. So why are Melo & Co. still at the top of Marc Stein's ranking of the dozen teams still playing in Rio?
The Los Angeles Lakers are negotiating a deal with former NBA forward and Chinese star Yi Jianlian, sources told ESPN.com.