An interesting deep-dive stat - how many times were we up one score and held the opposing team from scoring? I say that remembering the lone lead at OSU, their offense was terrible, and the moment they got down they walked through our D like we were on a bye week.
I think we probably beat Illinois with 10 more points as their momentum got going very late. For OSU it seemed like every time they opened up the playbook they had their way. That was a strange game.
It was a bad time to break, but it's not like they weren't trying before and just tried for that drive. They had to convert a fourth down, on that drive, I wouldn't call it "walking through" our defense. That's a really good offense, and in the second half we had held them to three 3 and outs and an INT which probably just wasn't sustainable.
To your question, do you want to count early game stops when we just went up a score?
UTEP - made them go 3 and out after each of our first 2 TDs. We did give up a TD in between those, but then also got a safety on their next drive.
Colorado - 4 and out (is that a thing?) on their drive after our first TD after a long kick return put our backs really against the wall, then a pick-six on their next drive after that. Then another 3 and out.
UNI - Allowed a 16 play field goal drive after going up 7-0, forced a punt after going up 14-3
Illinois - Allowed a field goal after we took a 10-7 lead. Forced a 3 and out out of halftime leading 17-10. Gave up a TD drive after going up 24-17.
Purdue - Forced a 3 and out after going up 7-3.
Rutgers - Forced a punt after going up 7-0. Actually stopped them on 4th and 3, but a very late false start call moved them back and they punted instead.
Indiana - Never had a lead to protect
Ohio State - As you pointed out, allowed a TD drive to relinquish the lead right after taking it.
UCLA - No leads to protect.
Other noteworthy moments that don't fit the criteria, but I think fit the vibe:
UTEP - After having a really bad 3 plays to allow them to tie it at 7, UTEP went 3 and out, safety, 3 and out, INT.
Illinois - We threw an INT after letting Illinois tie it at 10, and the defense made a 4th down stop. After Illinois tied it at 24, the offense had a
-13 yard 3 and out so you'd worry the momentum was gone. Instead, the defense forced Illinois into a 3 and out as well. Then after the offense bungled what should have been a go ahead drive, the defense stopped Illinois again to force OT.
Ohio State - After giving up the lead, the defense did get the ball back for the offense with 3:36 to play. Even with the big plays allowed, this has been OSUs worst offensive game by a decent margin. Penn State gave up fewer yards per play and only 20 points, but gave up a lot more 3 downs and total yardage/control of the game.
UCLA - After letting up the long TD to go down 27-7, UCLA only ran 13 plays (minus the kneeldown) for 44 yards, allowing the offense to claw back in.
Sorry for the essay, but I just don't think the defense consistently fails at the worst time. At that may not have been exactly your point. But the only times I see where the defense gave the lead back
right away were OSU and Illinois (let it get back to 10-10), and in both those cases they also got a stop right after to give the offense another chance. The defense is failing some fans eye tests not because it's been bad, but because the team isn't winning the games. And that's 95% on the offense, IMO.