Larry Bird, playing with a fractured left thumb, nevertheless led top-ranked Indiana State over bewildered Virginia Tech today, 86-69, in the second round of the NCAA basketball championship tournament.

The victory advanced the 30-0 Sycamores to the Midwest Regional semifinals Thursday against Oklahoma in Cincinnati.

Arkansas had little difficulty eliminating Weber State, 74-63, in the second game. The Razorbacks (24-4) have won 13 in a row and will face Louisville in the other Midwest Regional semifinal.

Bird, flinching from pain, still scored 22 points, grabbed 13 rebounds, handed out seven assists, blocked two shots and had a steal, as Indiana State made an impressive debut into NCAA tournament play.

A whirlwind 20-0 scoring explosion midway through the first half did in Virginia Tech, and, of course, Bird had his hand in most of that action.

He scored, rebounded and passed like a oneman destruction crew. He never dominated the game but always seemed to have it under his control, bad thumb and all.

"Indiana State is for real," Virginia Tech Coach Charles Moir said. "They took us right out of our game with their aggressiveness."

Bird fractured the tip of his left thumb in the Missouri Valley championship game against New Mexico State eight days ago.

The only protection permitted by NCAA rules was a soft, rubber casing and tape. He did not take any medication.

"He didn't shoot as many shots as normal and he didn't shoot as well as usual, either," said Indiana State Coach Bill Hodges, "But other than that I don't think the thumb gave him too much trouble."

Hodges considered an offensive adjustment to protect Bird's left side.

"We were going to make all of the plays for him going to the right, but he said not to, that we didn't have to change a thing." Bird took only 14 shots and made six of them.

The Gobblers, who had won nine in a row, jumped on top, 18-14, with 10:21 left in the first half, but quickly they were down, 34-18, and out of the game.

They went scoreless for seven minutes, 14 seconds. On Tech's 12 possessions in that span, they missed eight shots and had four turnovers.

Indiana State, meanwhile, was almost flawless and in one stretch Bird showed that he does not have to score a point to make things happen.

Bird scored only three points in the 20-0 run, all from the foul line, but his other contributions practically brought down the Allen Field House roof.

With Indiana State on top, 25-18, Bird rebounded Dexter Reid's missed shot to set up Carl Nick's three-point play.Then, after another Virginia Tech miss, Bird rebounded and cut loose a sizzling outlet pass resulting in Alex Gilbert's fast-break basket.

The Gobblers missed again on their next possession and again Bird rebounded. After head-faking the Gobblers into the air at the other end of the floor, he darted a sweet pass inside to Brad Miley for an easy layup.

Bird wasn't through yet. He stole the ball off Les Henson's dribble, looked one way and passed the other. Nicks grabbed it for an easy layup and the Sycamores led, 34-18.

Marshall Ashford borke the Virginia Tech drought with a short jump shot. Ashford, the Gobblers' primary ballhandler, missed six of seven shots and had six turnovers in the first half.

"We weren't patient or anything in that scoreless stretch," Moir said. "We just failed to make the big plays, ever."

Virginia Tech played a straight man-to-man defense most of the game with 6-foot-9 1/2 Wayne Robinson on Bird.

Robinson did fairly well by muscling Bird and keeping him outside much of the game. But Bird was content to feed his teammates and not interrupt the flow of the game.

"I thought we controlled him (Bird) pretty well," Moir said, "but we couldn't do anything with Nicks."

Nicks, 6-2 and 190 pounds can pop the jumper from 25 feet or muscle up the ball from inside. Tech's non-aggressive Gobbler guards succumbed to his tactics all day. And he hit for 22 points.

By controlling the boards, 45-38, Indiana State never let Virginia Tech get its running game going and the Gobblers scored fewer than 70 points only the fifth time this season.

Arkansas played its usual steady, mistake-free game. The Razorbacks shot 51 percent from the field, made 18 of 22 free throws and had only eight turnovers.

"It's pretty tough to beat a team when they do things as well as we did them today," Arkansas Coach Eddie Sutton said.

Arkansas' center, 6-11 Steve Schall, went nine for nine from the field and collected eight rebounds. All-American guard Sidney Moncrief had 19 points, five assists and five rebounds.

Weber State's David Johnson had 23 points, making 11 of 16 shots. The other Wildcats had a rough time contending with Arkansas' pressure defense

"They are just better than us," said Weber Coach Neil McCarthy, "and it showed."