The veteran guards scored 28 and 23 points, respectively, as the Buckeyes (5-0) downed the Lady Tigers for the second consecutive season.
Ohio State let an early 10-point lead slip away and went to the locker room ahead 32-30 then opened up some breathing room with a little more than seven minutes remaining.
Prahalis hit back-to-back three-pointers and forward Kaplana Beach finished a fast break with a layup to account for the Buckeyes' points in an 8-2 run that stretched a 52-50 advantage to 60-52 with 7:26 remaining in the game.
The Lady Tigers (3-3) drew within one possession one more time with a Jeanne Kenney layup that made ti 68-65 with 3:43 on the clock, but that was as close as they would get.
Hill answered with a three-pointer as the shot clock expired on the ensuing possession to double the lead again. Heaved from about five feet behind the arc at the top of the key, Hill's shot in the back of the rim, bounced up above the backboard and fell through the net, bringing most of the 3,474 in attendance at Value City Arena to their feet.
Prahalis made a career-high 6 three-pointers on 12 attempts and tied a career-high with eight rebounds. She also handed out eight assists and made two steals while playing all 40 minutes.
Hill was 5 for 10 from the field and 12 for 12 from the free-throw line while Beach added a career-high 13 points, grabbed six rebounds and blocked three shots in a career-high 35 minutes. The freshman forward from Westlake, Ohio, was 6 of 8 from the field.
LaSondra Barrett also scored in double figures with 13 points and four assists for the visitors.
Ohio State improved to 4-3 in the all-time series between the schools, a mark that includes a 59-55 win in Baton Rouge last season.