The Hoosiers built a 24-15 lead in the opening 15 minutes of the game, but the 15th-ranked Buckeyes (18-3, 9-1) outscored them 17-5 from there until halftime.
After coming off the mat, Ohio State led 32-29 at the half, a lead that grew to as many as many as 10 in the second en route to a 59-51 victory.
The Hoosiers (15-5, 8-3) never went away, but they never got within two possessions, either, after Star Allen hit a short jump shot in the lane to stretch the Buckeyes' lead to 40-35 with 14 minutes to play.
Allen, who had two key baskets during the comeback, finished with a game-high 21 points and 13 rebounds. She made 6 of 10 field goals and added a 9-for-11 performance from the free throw line to finish out her scoring line. The 5-10 senior also blocked two shots.
The freshman point guard also had six turnovers, but her line did not reflect the positive impact she had on the game, which drew 5,070 fans to Value City Arena.
"That's how lines can be deceiving," Ohio State head coach Jim Foster said. "I think she broke down the defense in the period when we needed her to break it down in the first half, and I think the threat is always there for her to make plays."
During the first-half comeback, Prahalis was often able to get into the lane to find teammates for high-percentage shots.
"One or two of those plays under the basket where she found Star and Jantel were high-degree-of-difficulty plays," Foster said. "The timing of them was terrific. We needed them. And having said that, she's got to get better at certain things and understand where her skill set can be a little more beneficial in the halfcourt."
Ohio State received the type of challenge it expected from the Hoosiers, who were 18-15 last season and start three seniors, a junior and a sophomore.
"I knew Indiana was a tough team," she said. "I think they've had a big turnaround. They have really good players and they've been together for so long. They're a seasoned team and we knew they were going to come in here and play hard being the No. 2 team in the Big Ten."
The two teams slogged through the first 10 minutes before Indiana was able to gain a bit of separation.
IU's Jamie Braun made a three-pointer in transition with 6:52 left in the half, causing Foster to call a timeout with his team trailing 24-15.
Whatever he told them did not have an immediate positive effect.
Both teams had a pair of empty possessions before Lavender and Prahalis went to work to get the Buckeyes on the way back.
Prahalis drove into the lane and whipped a pass to Lavender, who missed a layup but drew a foul. She made both free throws to finally get the Buckeyes off the 15-point mark after a scoreless stretch of 3:51.
After Whitney Thomas scored for the Hoosiers, it was Allen's turn to give her team a lift.
On consecutive possessions, she scored on putbacks to draw the Buckeyes within 26-21.
Prahalis then made 1 of 2 free throws and a long two-point jumper to cut the led to two.
Indiana looked like it would then be in business after a basket by Jori Davis and then a steal by Kim Roberson on the ensuing inbound pass, but Prahalis stepped in front of Roberson to draw a charging foul just outside the lane and stop the IU threat.
After Braun missed a step-back three-point attempt, Lavender took her turn again, making an up-and-under move to score a basket and draw a foul. She made the free throw to complete the three-point play and give the Buckeyes a 30-28 lead.
Thomas made 1 of 2 free throws for the Hoosiers, then Prahalis and Lavender hooked up one more time with the frosh finding the sophomore open for a jumper from 10-feet away that set the halftime margin at 32-29 in favor of the home team.
Davis was Indiana's high scorer. She scored 15 while Thomas added 12 and Bruan had 10.
Ohio State grew its Big Ten lead to one-and-a-half games over Indiana and kept that same margin over Purdue (15-7, 8-3), which won Sunday. Michigan State (15-6, 8-2) fell to one full game behind the Buckeyes. The Spartans play Monday night at Minnesota, and Purdue pays a visit to Value City Arena on Thursday night for a 7 p.m. tipoff.