Louisiana State guard Ethan Martin, one of three LSU seniors benched in a 10-point loss to Arkansas in the Great Alaska Shootout, led the Tigers to convincing revenge, 72-56, tonight in the semifinals of the NCAA Midwest regional.

The victory, before a record NCAA tournament crowd of 34,046 in the Louisiana Superdome, sends LSU (30-3) into Sunday's regional championship game against Wichita State. The Shockers shocked again tonight, beating Kansas, 66-65, on guard Mike Jones' two 28-foot jump shots in the final minute, the second with three seconds to play.

Kansas went into the final minute with a 65-62 lead and all-America guard Darnell Valentine on the foul line for a one-and-one. But Valentine missed and soon after missed a breakaway layup, setting up Jones' game-winner.

Martin is not an all-America, but he is the catalyst for LSU's fast break, as he showed tonight, collecting eight total assists and scoring 14 of his 16 points in the second half.

In the Shootout in November, LSU trailed by 18 points when Coach Dale Brown pulled Martin, forward Durand (Rudy) Macklin and guard Willie Slims. Senior center Greg Cook, a key rebounder and scorer tonight, didn't even make the trip, remaining in Baton Rouge for disciplinary reasons. Determined to teach his seniors a lesson for their lethargic play, Brown kept them on the bench. After that loss, LSU won 26 in a row before losing twice after clinching the Southeastern Conference title.

The Tigers are the highest-rated team remaining in the NCAA tournament and tonight they took advantage of Arkansas' impatience and dismal shooting, using the fast break to take an insurmountable lead. Martin and freshman forward Len Mitchell played exceptionally well for LSU.

The Tigers jumped to leads of 12-6 and 20-10 after missing their first seven shots. Cook scored 10 first-half points on dunks and layups as the Tigers led, 34-18, at halftime.

Arkansas (24-8) missed its first nine shots and made only eight of 25 from the field in that first half, allowing LSU to get into a rebound-outlet game, at which it may be the best in the nation.

The intimidating Tiger front court of Cook (l2 points, 10 in the first half), Macklin (15 points) and Mitchell (10 points) was expected to handle the Razorbacks. But the surprise was the ease with which Martin, Howard Carter and Sims (nine points off the bench) outplayed the Razorback backcourt of U. S. Reed and Darrell Walker.

Reed scored just four points in the second half, two on free throws. He disappeared the last 15 minutes while Martin was running wild through the Razorback defense.

Martin started poorly, picking up his third foul 12 minutes into the game. He went to the bench, but his replacement, freshman Johnny Jones, made a steal and assisted on a Mitchell dunk to give LSU an 11-point lead. Martin scored the Tigers' first six points of the second half, quickly taking advantage of Arkansas' defense, which was sagging and double-teaming Macklin and Mitchell with Cook on the bench with four fouls. LSU eventually led by as much as 24 points.

Arkansas Coach Eddie Sutton and Reed attributed the LSU victory to Cook.

"Greg Cook was the big difference," Reed said. "We were able to jump with them for a while but we just wore out. They have a lot of beef to go with their height. To win big, you have to be quick but you also have to have a couple of big men inside. LSU has that."

Tonight, LSU outrebounded the Razorbacks, 41-31 (in the Shootout, the Razorbacks enjoyed a 16-rebound edge). The Razorbacks' only true big man, 6-10 center Scott Hastings, scored a team-high 14 points.

In the opening game, Kansas led 65-62, with Valentine at the foul line. But he missed the first shot of a bonus free-throw situation. Wichita rebounded the miss and Jones, a 6-5 junior, made his first long jumper from the left side with 48 seconds left. That made it 65-64.

Kansas inbounded the ball to Valentine, but the senior guard missed a breakaway layup, the ball rimming out to Shocker forward Cliff Levingston. He cleared it upcourt and Jones, standing outside of the Nba's three-point ring, swished the jumper with :03 showing on the clock.

The Jayhawks tried a trick inbounds play after a timeout with two seconds left. Guy ran the length of the baseline under his own basket, drawing his defender, Shocker forward Jay Jackson, to him.

Jackson ran over Valentine, who had sneaked up to position himself in front of Jackson and draw the foul. But the officials made no call. With the trick play revealed, Kansas called another timeout, and this time Guy sailed the ball into the crowd at the other end, giving the Shockers possession and the game.