LOS ANGELES -- As Reeves Nelson goes, so goes UCLA.
He's the emotional leader for the Bruins, an intense, tattooed human barometer whose energy level dictates that of the rest of the team.
He's the team's resident drill sergeant, constantly barking at teammates and even coaches during games.
When Nelson pays hard, the Bruins follow suit. When Nelson plays well, UCLA wins more often than not. When Nelson has energy, it fires up the team.
So it's no surprise UCLA played its most complete game of the season when Nelson played his.
The Bruins thumped No. 10 Arizona 71-49 in the final men's basketball game at Pauley Pavilion before the facility is shut down for a year-long renovation project.
Nelson played the part of bulldozer, razing the Wildcats for a career-high 27 points and adding 16 rebounds -- one short of his career high -- as the Bruins (21-8, 12-4) forged a tie with the Wildcats (23-6, 12-4) for first place in the Pac-10.
But the numbers on Nelson's stat line pale in comparison to the job he did defensively after begging for the opportunity to guard Arizona forward Derrick Williams, a leading contender for Pac-10 player of the year and a projected first-round NBA selection.
So while John Wooden's great-grandson brought UCLA coach Ben Howland to tears by making the final basket in Wooden's old stomping grounds, Nelson brought the Wildcats to their knees with a virtuoso performance that will probably get lost in the hoopla of the circumstances but will probably lift UCLA into the national rankings for the first time in nearly two years.
"Reeves Nelson had the game of his career to this point," Howland said. "This is by far our best game of the year. This was the best 40 minutes."
It's a fine line Nelson walks, sometimes bringing the team down when his mercurial persona falls into a lull, and other times injecting a surge of energy. Some say there are two sides to Nelson: Good Reeves and Bad Reeves.
Bad Reeves occasionally drags the team down by sulking when things aren't going his way. He sometimes triggers defensive lapses when he forgets to hustle back after making a turnover. Sometimes he doesn't make the effort to block out if he's still caught up in a foul call that didn't go his way.
Good Reeves showed up Saturday, hustling for loose balls, fighting for rebounds battling inside and making strong moves from all around the basket. But his defensive performance turned this into Really Good Reeves.
Williams torched UCLA last month in Tucson, scoring 22 points and delivering several highlight-reel worthy dunks. Nelson asked Howland earlier this week for the assignment, but Howland had Anthony Stover and Joshua Smith on Williams to start the game.
Williams appeared to be on pace for another huge game with 13 points on 4-for-7 shooting with 5:22 left in the first half. That's when Nelson got in Howland's ear.
"I remember Reeves saying, 'I want him, Coach. Don't take me out when he's in the game,'" Smith said. "'When he's out of the game, you can take me out.'"
Nelson remembered it this way: "I went right up to Coach and said, 'I'm going to guard him the rest of the game no matter what,'" he said. "It was a strong request."
Williams had only two points on 1-for-4 shooting the rest of the way. And Nelson wasn't hacking Williams to keep him at bay. Williams, the nation's leader in free throw attempts, did not get to the foul line while Nelson was guarding him.
"I know he's a really great player and he's going to play basketball for a long time for a lot of money," Nelson said. "I just tried to do my best to make it difficult for him. I knew if we did a good job on him, we'd have a good chance of winning the game."
Sometimes Nelson rubs people the wrong way. He can be brash and even downright rude, with little filter for saying what's on his mind.
Saturday, for instance, he called out a reporter for intimating that he was a weak defensive player.
"I've been told that some people say I can't play defense really, so I just take that very personally," he said. "If Derrick Williams is a top-five pick in the NBA and I hold him to two points in the second half, I think I'm proud of my own effort."
Stover acknowledged Nelson can sometimes go over the top, but said he's also misunderstood.
"He's a really emotional person and it comes out the wrong way sometimes, but he always means the best," Stover said "He breathes on everyone the hardest because he's driven to win and he pushes us to do that."
Forward Tyler Honeycutt, however, said Nelson has made great strides toward keeping his emotions in check.
"He's stronger mentally," Honeycutt said. "He's not letting little stuff get to him. He's improved as a player as well as person -- being patient, being able to listen and being coachable."
Nelson embraces the role of emotional leader. He relishes the idea that he can inspire the team when it needs inspiration and that he can energize the team when it hits lulls. But he realizes things can go the other way, too.
"I try my best not to let my emotions get the best out of me positive or negative," Nelson said. "I'm still working on that as well and that's probably the most difficult part of my game."
After Saturday's game, Nelson regained the team lead in scoring with 14 points a game and he also leads the team in rebounding with nine a game. It's no surprise that some of Nelson's lowest scoring games of the season -- five points against Kansas and Montana and seven against California -- resulted in Bruins losses, because as Nelson goes, so goes UCLA.
But it's his perch as the team's emotional leader that has as much influence on how UCLA plays as any statistics he puts up.
"We feed off of each other so as soon as his emotion is up to his peak, we have to play with him," Stover said. "We have to play as a team and we all played to Reeves' level tonight."
On Saturday, that level was pretty high.
Peter Yoon covers UCLA for ESPNLosAngeles.com.