Murray State got awfully close to a second straight bracket-busting upset before Butler reminded the Racers which small school almost always plays big in March.
Ronald Nored's three-point play snapped a tie with 25.4 seconds left, and Butler narrowly evaded a second stunner by the 13th-seeded Racers in three days, advancing to the regional semifinals of the NCAA tournament with a 54-52 victory Saturday in San Jose, Calif.
Nored scored 15 points and Gordon Hayward had 12 before making the decisive defensive play for the fifth-seeded Bulldogs (30-4), who extended the nation's longest winning streak to 22 games.
Butler advanced to the round of 16 for the second time in four years - but only after surviving a thriller against the undersized but big-hearted Racers (31-5), who beat fourth-seeded Vanderbilt in the first round on a buzzer-beater.
In next week's West Regional semifinals in Salt Lake City, Butler will face the winner of top-seeded Syracuse's meeting with Gonzaga on Sunday.
Isaiah Canaan scored 14 points and hit four 3-pointers for the Racers, who matched Butler's sturdy defense and outrebounded the Bulldogs 39-22.
After Butler's Matt Howard made one of two free throws with 17.2 seconds left, Murray State had a chance to set up for a final shot - but instead of creating a new play during a timeout, as the Racers did before Danero Thomas' jumper beat Vandy, Murray State simply got the ball to Canaan.
The guard was double-teamed, and his frantic attempt at a perimeter pass went off Hayward's hand and rolled into the backcourt, setting off a celebration down near Butler's bench.
Thomas, whose 15-footer beat Vanderbilt 66-65, was held scoreless by the Bulldogs in 26 minutes.
The early second-round game at the Shark Tank matched two teams with a combined 41-1 record in 2010, both carrying rich basketball traditions from smallish schools. Although the Racers were compelling candidates to carry the small-school banner into the tournament's second weekend, Butler has been doing it for years - and with an enrollment that's less than half of Murray State's 10,500.
Still, Murray State got agonizingly close to its first-ever trip to the regional semifinals before Butler finally showed its hard-earned poise from several years as the cream of the mid-majors.
Midwest RegionalTENNESSEE 83, OHIO 68:
J.P. Prince scored 18 points, and Brian Williams and Wayne Chism had 12 rebounds apiece on Saturday to lead sixth-seeded Tennessee over No. 14 seed Ohio in the second round of the NCAA tournament.
It's the third time in four years Bruce Pearl's Volunteers have reached the NCAA's second weekend. Tennessee (27-8) will play the winner of today's Ohio State-Georgia Tech game in the Midwest Regional semifinals in St. Louis.
Tommy Freeman scored 23 points for Ohio, which was the lowest seed to get out of the first round. But he got little help from Armon Bassett and freshman D.J. Cooper, the guards who starred in the first-round victory over third-seeded Georgetown but combined for 23 points on 7-of-23 shooting against Tennessee.
Each of Saturday's games in Providence matched a double-digit seed against a team from a power conference. But one-half hour after tiny Saint Mary's knocked off Villanova - a No. 2 seed - Ohio failed in its attempt to be just the third No. 14 seed to reach the Sweet 16 since the tournament expanded to 64 teams in 1985.
The Bobcats (22-15) trailed by six points midway through the second half before the Vols went on a 10-1 run to put it away.
Scotty Hopson scored 17 points, and Bobby Maze had nine assists for Tennessee, which continues its remarkable run since four players were arrested on New Year's Day - three of them were suspended, and starter Tyler Smith was kicked off the team - in a traffic stop that resulted in gun, drug and alcohol charges.
Two games later, with six scholarship players and three walk-ons, the Vols beat No. 1 Kansas.
The Bobcats earned their underdog status honestly: They were 7-9 in the Mid-American Conference this year and a No. 9 seed in the 12-team league tournament. But they swept through though the MAC postseason and then dispatched the Hoyas 97-83.