Coach John Thompson said the Hoyas have never played worse offensively and still won in his 10 years at the school. But Georgetown's second-half defense shut down Louisville in a 50-46 victory today that advanced the Hoyas to Monday's NCAA championship game against top-ranked North Carolina.

A record indoor basketball crowd of 61,612 in the Superdome watched North Carolina (31-2) defeat Houston, 68-63, in the opening game of the semifinals before the Hoyas (30-6) unraveled a tough, experienced Louisville team (23-10).

Georgetown--which last appeared in the final four in 1943, losing to Wyoming in the title game--and North Carolina play for the national title at 8:12 EST. There is no consolation game.

Today, the Hoyas were a much different team from the one that shot a tournament record 74.4 percent in one game and a record 63 percent for three games in winning the West Regional. The Hoyas looked tentative offensively, making only 18 of 41 shots (43.9 percent) and committing 18 turnovers.

But their defense held Louisville to 19-of-48 shooting (39.6 percent) in this relentless, physical game. Louisville also had been shooting at a tournament-record pace (59 percent) before today.

Eric Smith, whose eight straight points midway through the second half keyed a decisive 14-4 run by Georgetown, led all scorers with 14 points. Eric Floyd, making three of 11 from the field, finished with 13. Patrick Ewing had eight points and 10 rebounds, but generally was the difference defensively. Derek Smith led Louisville with 10 points.

"I can't remember us appearing to play so poorly offensively and still winning the game since I've been at Georgetown," Thompson said. "We had to strain for everything we got. You have to attribute our poor offensive game to Louisville's defense. A lot of things happened out there we didn't like."

Thompson had to love his team's stunning defensive effort in the second half. The quicker Cardinals had scored back-to-back baskets for only the second time in the game, cutting the deficit to 35-34 with 11:37 to play.

Smith then got free for an uncontested layup. Louisville's Jerry Eaves missed a long jump shot and Ed Spriggs, who was instrumental inside for the Hoyas during his 20 minutes with five points and seven rebounds and his strong defense, got the rebound.

Operating out of a semidelay, Smith slipped inside for another layup, this one a driving left-handed shot that sent him sprawling and Georgetown into a 39-34 lead with 10:13 left. It would be Georgetown's final basket.

"We were just being patient and looking for only good shots," said Smith, the Hoyas' defensive leader. "Louisville is a good defensive team and they didn't give us much."

Smith then made two free throws, Ewing two more and Floyd four straight and Louisville trailed, 47-38, with 3:14 left.

The Cardinals, who earlier had pulled ahead, 30-29, on Wiley Brown's basket, missed six of eight shots and committed four turnovers in falling behind. With Ewing and Spriggs in the middle, the only shots the pressing Cardinals got were perimeter jumpers.

"We were getting good shots--they just weren't falling," said Eaves. "We started rushing and making turnovers and that didn't help us. They spread their 1-3-1 zone defense out and were also able to clog the middle. But even so, we got good shots."

Georgetown was running its delay game expertly now. Except for two mistakes by Fred Brown and four missed free throws in the final 2 1/2 minutes, the Hoyas did little wrong. But there were some tense moments until Brown made both free throws in a one-and-one situation to make it 49-44 with 44 seconds to play.

Unable to get in the fast-paced game it would have preferred, Louisville had to play a half-court game. The good-percentage shots didn't come easily. A basket by Lancaster Gordon, his only one of the day, and a goal-tending call against Ewing on a shot by Charles Jones got Louisville close, 47-42, with 1:47 left.

Louisville had two chances to get closer after forcing turnovers. The first time, Ewing intercepted a low lob pass intended for the 6-foot-8 Jones. The second opportunity resulted in a charge by Rodney McCray, his fifth foul.

The Cardinals cut the deficit to 47-44 when Poncho Wright made two free throws with 1:08 left.

"We had to just keep on working and take away what they like to do best--run," said Fred Brown. "I knew I made a couple of mistakes but I didn't worry about them. I just went back out and tried to forget it. We just stayed with our man defense and kept scrambling."

Brown atoned for any mistakes when he made the two free throws with 44 seconds left. Smith's desperation bank shot with 13 seconds left again pulled the Cardinals within three points, but that was as close as they would get.

"I thought their defense was the difference," said Louisville Coach Denny Crum. "They kept us from getting the good-percentage shot. We made too many turnovers that weren't forced. I didn't think turnovers would beat us; I thought we would handle the ball better. Tonight just wasn't our night."

Crum should have realized that in the first 20 minutes. The Cardinals shot 50 percent while averaging 75 points per game this season, but missed 19 of their 29 first-half shots and four of six free throws; they were outrebounded, 21-16. Georgetown didn't play much better, making 12 of 26 from the field in taking a 24-22 halftime lead.

As poorly as the Hoyas played offensively in the opening half, they still had chances to break the game open. Two key plays by Anthony Jones helped Georgetown pull away from a 12-12 tie to an 18-12 lead. The freshman from Washington's Dunbar High School made a layup on one of the few fast breaks either team was able to pull off, and also made a steal and layup.

The lead didn't last. Louisville blocked two shots and got baskets from Smith and Eaves to get close at intermission.

But the Hoyas decided at halftime to play a tight man-to-man defense in the second half. The Cardinal guards--Eaves, Gordon and Milt Wagner--couldn't get away from their defenders for the shots they wanted and Ewing and Spriggs didn't give up any layups. The three made only six of 19 shots.