While top-seeded West Fork, the defending tourney champs, were on fire from behind the arc early, Quentin Houghtaling took care of the heavy lifting for the eight-seeded Longhorns in the first period.
Houghtaling racked up nine of Viola's 11 points in the opening stanza. He finished with a game-high 16 points for the Longhorns.
The tone for much of the contest was set right off the bat, as West Fork's Josh Ferrell opened the proceedings with a 3-pointer for the Tigers.
Tim Seaman followed that up by hitting four of West Fork's (15-3) treys in the first period, helping the Tigers to a 19-11 lead after one.
Devin Brown hit a couple of free throws to start the second for Viola (14-7), but West Fork responded with back-to-back 3-pointers from Aaron England to push the Tigers on top 29-15.
The Tigers held a 37-21 advantage at intermission.
Dolan Johnston (13 points) got rolling for Viola in the third period, reeling off eight straight points for the Horns.
But West Fork refused to yield and after England hit another 3-pointer late in the stanza, the Tigers led 49-34 after three.
Keith Martin finished with four points for Viola, while Brandyn Batterton added two and Austin Gardner one.
In opening-round action Jan. 4, the Horns edged past Omaha 66-63 in overtime.
Gardner exploded for a game-high 29 points, while Houghtaling had 11 and Johnston 10.
Viola led 13-5 after the first period, 29-21 at the half and 44-35 after three periods of play.
Omaha rallied in the fourth to lock things at 60-all after regulation play.