A crowd of 3,497 populated Value City Arena to watch the Buckeyes (16-9, 7-6) knock off a ranked team for the fourth time this season.
The 23rd-ranked Lady Lions (21-7, 10-4) committed 27 turnovers that led to 30 Ohio State points.
"The turnovers were the difference in the game," Penn State head coach Coquese Washington said, attributing them to "some bad decisions" and "a little looseness with the ball, so to speak."
She also lamented how many of the miscues came in live-ball situations.
"We turned the ball over and they were able to go down and score in transition," she said. "Ohio State is just a dangerous team in transition."
Officially, the Buckeyes got credit for 10 fast-break points, but their defense contributed to a tempo that had them looking more like the confident group of veterans they were expected to be when the season started than a team that endured a 6-9 stretch from mid-December to the first game of February.
"We're getting better," head coach Jim Foster said. "We have a better understanding of who we are and who we need to be to be a very good basketball team. I think our intensity and focus on defense is better. Our attention to detail on the game plan is better. Our freshmen are now playing in a way that it would be difficult to realize they're freshmen."
Ohio State took control of the game with an early 9-0 run that broke a 6-all tie.
From the 13:23 mark until there two minutes left in the half, the lead ranged from as low as six to as high as 12. Then it reached a new high on a historic play by Samantha Prahalis.
The junior point guard who came to Ohio State with a reputation for flashy passing tied the Jamie Lewis' career school record for assists with a vintage behind-the-back bounce feed to Lavender, who swished a jumper to put Ohio State ahead 40-26 with 1:58 on the clock.
Prahalis set a new assists standard 1:36 later when she found Hill open in the corner for a three-pointer that made it 45-30 with 22 seconds left.
Penn State scored the last point of the half on a Zhaque Gray free throw, but there was no doubt the Buckeyes dominated the opening 20 minutes.
They led 45-31 while shooting 50 percent (17 for 34) from the floor.
Penn State made 13 of 22 (59.1 percent) of its field goals but butter fingers killed the visitors. They committed 15 turnovers that led to 14 Ohio State points.
Lavender led the way with 12 points while Hill added nine.
Lady Lion point guard Alex Bentley, who was magnificent in Penn State's 80-71 win in State College on Jan. 30, picked up two fouls in the first four minutes and was in and out of the lineup the rest of the half with her team's offense struggling as a result.
With Hill pursuing her wherever she went, Bentley never found much of a rhythm in the second half, either. The sophomore finished with four points, five assists and five turnovers in 22 minutes.
Early in the second half, Prahalis stretched the Ohio State lead to 19 with back to back baskets, first a running back shot then a three-pointer that made it 56-37 with 16:26 on the clock.
The Buckeyes' lead peaked at 23 with 14:40 to go, and though the Lions mounted a comeback, they never got closer than 10 the rest of the way.
Lavender was the game's leading scorer (23 points) and rebounder (11), and Prahalis gave Ohio State a pair of double-doubles as she totaled 21 points and 11 assists.
Hill finished with 19 points, five boards, three steals and a pair of assists.
Gray and Mia Nickson had 14 apiece to lead Penn State.
The win improved the Buckeyes' hopes of earning a bye in the Big Ten tournament and making the NCAA tournament, but it did not keep their hopes of a seventh consecutive conference championship alive.
The top five teams in the standings earn opening-round byes in the conference tournament, and the Buckeyes head into the penultimate weekend of the season tied with Purdue for sixth-place.
Ohio State's previous assists leader was Jamie Lewis, who had 643 from 1997-2001.
Prahalis finished the night with 647 career helpers.