CHARLOTTE - It's unlikely, but possible, that North Carolina's high-scoring basketball team could clank shots in the East Regional final tonight against Louisville.

That happened in last March's regional championship game against Georgetown, when the Tar Heels inexplicably turned snowball cold, blew a substantial lead and lost the game, 96-84 in overtime.

That loss has stuck like a motivational spur in their heels -- and minds. Back again, they believe they are better prepared to leap the regional hurdle, avoiding the pitfall and pain of a year ago.

They are more mature, more experienced, more focused, said junior sixth man Danny Green -- and more defensive. While the Tar Heels can flat-out run, shoot and illuminate the scoreboard, they are cognizant that solid defense is essential as well and are improving at that end of the floor.

"I think [our defense] does get overlooked," coach Roy Williams said. "We worked harder, and we've gotten better and better. It's a big key for us."

That Carolina could defend as well as shoot became especially evident on March 8, when the Tar Heels defeated Duke 76-68 with trickery and tenacity at Cameron Indoor Stadium.

Switching on ball screens, they covered more closely the Blue Devils shooters, who hit just 32.9 percent of their shots and failed to score in the last 5:42 of a game that propelled UNC to the ACC regular-season title.

The Heels had more sustained, hard guarding again in Thursday's 68-47 regional semifinal win over Washington State, which shot 31.6, a percentage also partly attributable to the Cougars' chilled shooting touch.

"We've got great pride in [defense]," insists Wayne Ellington, better known for his long-range shooting. "We're stopping drives and getting help [from the weak side]."

Quentin Thomas added that the Tar Heels are more alert and communicating better, limiting breakdowns.

"They pressure the ball well and get deflections," said Louisville's Jerry Smith. "You've got to run your motion sets all the way through to the end [against them]."

On the perimeter, the Tar Heels are guarding screens on the ball and fighting through picks with stronger frequency while big men Tyler Hansbrough, Deon Thompson and Alex Stepheson are contesting shots harder inside, Tar Heels assistant coach Jerod Haase said.

They also are finishing their defensive stands with robust rebounding. In three NCAA Tournament games, Carolina has a plus-15 margin on the boards.

It suggests that, in practices, grinding through about 14 different defensive stations and Williams' harping on becoming stoppers has paid off.

"I think [the players] better appreciate that to win in the Sweet 16, you have to do it at the defensive end," said Haase, aware that even a team with a plethora of scorers can have an off night shooting.

Remember Georgetown.

"It's in the back of our minds," guard Ty Lawson said. "That's what gave us the motivation throughout the summer to work hard, get back to this position and hopefully past this position. We've been waiting for this moment since last year, since we lost."