Hulls finished with 20 points, Zeller had 19 and Watford finished with 14 as the Hoosiers (25-7) moved into the quarterfinals Friday and a game against No. 12 Wisconsin (23-8).
Iowa, Minnesota and Purdue moved on with first-round victories Thursday.
The Hawkeyes nipped Illinois 64-61 to set up a faceoff with top-seeded and eighth-ranked Michigan State, Minnesota produced a 75-68 overtime victory over Northwestern and will take on No. 13 Michigan, and Purdue ran away from Nebraska 79-61 to create a matchup with No. 7 Ohio State.
A second-half cold spell by the Nittany Lions allowed Indiana to take control. The Hoosier ran off 14 straight points in the period to push its advantage to 54-34. Penn State (12-20) got a game-high 26 points from Tim Frazier.
Iowa (17-15) picked up its win behind 20 points from Matt Gatens. The Hawkeyes won despite not making a field goal after Gatens hit a jump shot with 9:17 to go. The Hawkeyes did have seven free throws -- the last four by Gatens -- the rest of the way.
Illinois (17-15) lost 13 of its last 15 games.
Minnesota's Andre Hollins scored with 55 seconds left in regulation to create overtime and the Golden Gophers scored the final six points of the extra period against Northwestern.
Hollins scored 25 points to lead the Gophers (19-13). Northwestern (18-13), which shot just 35 percent from the field and grabbed a mere five offensive rebounds, was paced by JerShon Cobb with 24.
Purdue (21-11) made 13-of-25 shots from 3-point range and Anthony Johnson scored 17 points off the bench. The Boilermakers broke the game open in the second half to end Nebraska's first basketball season in the Big Ten.
Bo Spencer scored 22 points for the Cornhuskers (12-18).