Lou Williams can be a shooting guard or a point guard. A starter or a sub. It all depends on the situation.

The role Williams is now entrenched in, at the ripe old age of 21, is mentor.

"When I broke into the league, I thought the game had to go 100 miles an hour all the time," said Williams yesterday after a light workout at Philadelphia College of Osteopathic Medicine, following the Sixers' 98-92 win over the defending champion Boston Celtics on Wednesday. "I learned that things had to slow down, that I had to slow down. That's what I'm trying to tell these guys, too."

The guys to whom he referred were second-year player Thaddeus Young (20) and rookie Marreese Speights (21).

All were instrumental in the Sixers' win over Boston. Williams deposited a game-high 27 points, including 16 in the decisive fourth quarter. Young, starting at small forward, contributed 21 points and Speights chipped in eight points in 19 minutes in his first NBA action.

While the primary focus of the Sixers has centered on the acquisition of forward Elton Brand (11 points in 22 minutes), many are just as excited at the play of the Sixers' young guns, who include Williams, Young and Speights.

"It's very different. This year, I'm playing a lot at the 'three' and last year I was playing the 'four,' " said Young, who started 22 games last season.

But he'll have help, courtesy of Williams.

"When I first got into this league, it was hard because I felt like I had to do too much," said Williams, who is entering his fourth season. "But I realized what made me play well in high school and wherever I played was just playing my game. It's what worked for me.

"That's something that Thad figured out earlier than I did and that's something I'm trying to pass along to Marreese. Guys come to the NBA and start thinking too much and worrying too much about what the coach is saying instead of doing the things that got them here. That's one of the basic messages. That it's all mental."

And physical, according to coach Maurice Cheeks.

"The hardest part [for young guys] is the physical part," Cheeks said. "They have to pick up a lot of things offensively and defensively, but the hardest part is the physical part. I don't think [Speights] knew how physical the NBA was, particularly the low post. I mean, he gets hit every day by Reggie [Evans], who hits everybody. He has to be able to pick up the education part, and the physical as well."

He'll have help. Mostly from the cagey vet, Williams. If you can call a 21-year-old that.

Six shots