After a half in which it scored only nine points despite not being in a slowdown, defending NCAA champion North Carolina showed the potential of its young, struggling team and rallied to defeat Louisiana State today, 47-43.

Guard Buzz Peterson, a sophomore who hardly played in critical situations as a freshman, brought the Tar Heels back with his outside shooting (nine of 11 for 18 points, all in the second half).

Then teammates Sam Perkins and Michael Jordan made most of the big plays, Jordan making three foul shots in the final 37 seconds.

Perkins' steal with 40 seconds to play, when the Tigers (3-2) tried to protect a 43-42 lead with a delay game, gave North Carolina (2-2) the opportunity to win.

The crowd of 8,140 in Brendan Byrne Arena booed the Tar Heels when they left the court at halftime after they went almost 11 minutes without making a field goal.

UNC shot 25 percent (four of 16) and committed 13 turnovers that led to 15 of LSU's 21 points in the half.

"I felt like it was a home crowd in the second half; maybe they felt sorry for us," said Dean Smith, North Carolina coach. "They should have booed when we went off . . . We've never been more embarrassed in a half in 21 years."

North Carolina's problems were a combination of its lack of mental readiness to play and an aggressive LSU defense that cut off the passing lanes. Only their half-court defense kept the Tar Heels within 12 at the half. "In the second half, I faked the first perimeter pass," said point guard Jimmy Braddock. "And then we could get it to the man we wanted."

That was usually Peterson, who also was open in the first half, but didn't get a shot. "The first half will be a big lesson to us," Peterson said. "It showed us how we weren't up for the game at all."

But the second half was different, the most contrasting two halves of any game in his college career, said Braddock, a senior.

The Tar Heels caught up and went ahead in less than eight minutes, Peterson making five straight shots, and LSU was on its way to becoming 3-2.