Nevada-Las Vegas, coming off its toughest win of the season, remained the unanimous No. 1 choice Monday in the United Press International college basketball ratings, while Ohio State took over second place.

The Runnin' Rebels, who beat previous No. 2 Arkansas 112-105 on Sunday, swept the balloting for the ninth straight week. UNLV earned all 40 first-place votes cast Monday by the 42-member Board of Coaches and finished with 600 points.The University of Utah, which defeated Hawaii and San Diego State last week, moved up two places to No. 13. The Utes are now 22-2 for the season and meet Wyoming and Brigham Young University this week with the opportunity to clinch the WAC championship if they win both games.

The Rebels came back from a four-point halftime deficit against Arkansas to put together a 10-2 spurt to begin the second half and led by as many as 23 points before the Razorbacks closed the gap in the final three minutes.

"I don't know how you can play any better than we did the first 17 minutes of the second half," UNLV Coach Jerry Tarkanian said after the Rebels, 20-0, ran their winning streak to 31 games.

UNLV's performance also impressed several opposing coaches, including one who was in attendance in Fayetteville, Ark.

"I think Nevada-Las Vegas really established themselves," Missouri Coach Norm Stewart said. "They truly are a tremendous team. They seem to be well-focused. When you look at that, (it seems) the only thing that could derail them possibly is themselves and they seem to be so well-focused that you don't even see that happening. It's a tremendous basketball team."

UNLV is attempting to become the first team to win back-to-back national championships since UCLA in 1972 and 1973 and the first to take the title with an undefeated record since Indiana in 1976. The last time a team finished the regular season unbeaten was 1979, when Indiana State and Alcorn State turned the trick.

"I think you just saw why a lot of people believe this (UNLV) team could compete with some of those in the NBA," Arkansas Coach Nolan Richardson said.

Ohio State, which improved to 19-1 by routing Northwestern in its only game last week, moved into second place with 526 points. Arkansas slipped to third with 510 points and Indiana held fourth with 494.

Duke took advantage of an Arizona loss to move up one place into fifth. The Blue Devils posted three wins last week, including an impressive 88-70 triumph Sunday against Louisiana State.

"We lost to the best team we have played this year," LSU Coach Dale Brown said. "We have never seen that kind of defense. They hustled from beginning to end. We got whipped."

Arizona dropped one spot to sixth, while two losses by St. John's allowed No. 7 Syracuse, No. 8 North Carolina and No. 9 East Tennessee State each to move up one position.

Southern Mississippi broke into the Top 10 for the first time this year after improving two positions. Kansas leaped six spots to 11th and St. John's wound up 12th, a fall of five places.

No. 13 Utah moved up two places, No. 14 UCLA dropped three and No. 15 New Mexico State gained one. No. 16 Nebraska slipped two notches and No. 17 Georgetown improved two places.

No. 18 Virginia plummeted five spots after suffering three losses in four games last week. No. 19 Oklahoma State and No. 20 Alabama each improved one position and No. 21 Texas moved up three.

No. 22 Michigan State returned to the ratings after a two-week absence and fellow newcomer Wake Forest was 23rd. Completing the list were Louisiana State and New Orleans, tied for 24th.

Dropping out of the ratings were Oklahoma, tied for 22nd before back-to-back losses last week, and Mississippi State.

The Atlantic Coast Conference placed four members in the Top 25 this week, while the Big East, Big Eight and Big Ten each were represented by three teams.

Kentucky, 17-5, is one of seven schools ineligible for the NCAA Tournament and the UPI ratings.