As Dale Brown walked off the court at halftime today he glanced up at the scoreboard. It told him his Louisiana State team was leading Indiana, 30-27, in their NCAA tournament semifinal game.

Brown also knew that Hoosier star Isiah Thomas has three fouls. "I thought we had the game under control then," he said. "I would have bet anything we were going to win."

He would have lost the bet, too. The next 20 minutes were among the most miserable he has had as a coach. Even with Thomas playing just nine minutes, the Hoosiers defeated the Tigers, 67-49, holding them to 19 points in the second half to advance to Monday's national final against North Carolina.

The Tigers (31-4) shot only 24 percent the second half, once missing six straight shots. They didn't score during the first four minutes while Indiana was getting 11 points, and after 17 1/2 minutes they had just nine points.

"We were worst," said Durand Macklin, the most miserable Tiger with two-of-12 shooting for the day. "We just blew it. They weren't unbeatable at all."

There were three key elements to this game. One was Brown's decision to slow the tempo and rest point guard Ethan Martin after Thomas picked up his third foul with 3:14 left in the first half. That allowed Indiana to get to the half trailing by just three when it could have been worse.

Another was a short, staccato speech Hoosier Coach Bob Knight gave his players at the half when he told them to relax and play the kind of controlled, poised basketball they demonstrated throughout the Mideast regional.

Perhaps the most important element was Jim Thomas, the sophomore guard who came in for Isiah Thomas after the latter picked up his fourth foul with 16:33 left and Indiana leading, 36-30. During the next 10 minutes, Thomas got nine rebounds and two assists while shutting down Martin. By the time Isiah Thomas came back with 6:47 to go, the Hoosiers led, 54-39, and it was over.

"Jim was the key guy today," said Isiah Thomas, who managed 14 points and four assists despite the fouls. "I don't think anyone even noticed I was out."

Every person in the Spectrum noticed when Thomas was called for his third foul with 3:14 left in the first half. And almost everyone was stunned when Brown sent Johnny Jones in for Martin, his own superb point guard, then ordered a spread offense with the Hoosiers in trouble.

"We went to our 2-1-2 offense to try to get Greg Cook the ball inside," Brown said. "I took Martin out because I was afraid he might pick up his third foul because he would have a letdown seeing Thomas go out and do something careless".

Neither team scored the rest of that half. The Hoosiers (25-9) shot only 36 percent each half and were outrebounded, 24-18, the first period. With Thomas in foul trouble, they appeared to be introuble. Knight sensed his players were tight.

"Relax," he told them during the break. "You're getting good shots but you're rushing. You're goosing the shots up there like you get a point for hitting the backboard."

"We were too pumped up," Thomas said. "I was up at 6 a.m. today, ready to play then. I think we were all like that."

After its coach had finished his speech, a different Hoosier team returned to the court. Ray Tolbert, who has been Mr. Inside to Thomas' Mr. Outside the last six weeks, remembered thinking as he warmed up for the second half, "This is my last year.

"I kept looking up at the clock, knowing we only had 20 minutes to get it done. I knew that Landon (Turner) and I really had to go to the boards hard the second half.We hadn't done that the first half."

On Indiana's first possession of the second half, Ted Kitchel, threw up a jumper that hit the front rim. Tolbert cleared out half the state of Louisiana. grabbed the ball and slammed it home. It was only two points, but it was a message. The tone was set.

Turner, high man in the game with 20 point, sank a short hook to put Indiana ahead for good. Macklin missed at the other end and Thomas fed Turner of a three-point play. Turner tapped in another Kitchel miss and it was 36-30.

"Then came the brief moment of worry when Thomas picked up his third foul.

"We knew the other Thomas was pretty good, but not that good," said Martin, held to two of eight from the field. "In the second half we started to panic when we couldn't get it down low. We started throwing up some Hail Marys from outside. I blame ourselves more than their defense."

Whoever was to blame, LSU made only seven of 29 shots that half. Indiana didn't improve its shooting, but didn't need to. The Hoosiers also outrebounded the Tigers, 25-17.

The last time LSU was close was at 40-34 with 14:05 remaining, when Howard Carter, high for his team with only 10 points, hit a driving 10-footer. Indiana scored the next eight points to make it 48-34 and the rest of the way the Tigers merely were waiting for the end.

"All the shots we missed in a row, five in a row at one point I think, seemed to break our spirit," Brown said. "It was the first time all year I think the kids looked around and said, 'Wow, we might lose this game.'"

Indiana now has won four tournament games by a a total of 100 points and is one step from regaining the title it won here five years ago.

"As long as we keep from getting too excited like we were early today, I think we'll be all right," and Kitchel, who had 10 points. "That thing about this team is we know what we have to do to win. At the half, Coach didn't have to say much. We all knew. We were still in control."