He had a sack (and rarely blitzes), several tackles and several pass breakups. In Q1 when Graham got most of his rushing yards, Teo was getting blocked by 2 players on most running plays. After ND adjusted, they controlled the LOS much better, which freed Teo and, when their back was up against the wall, Teo led the charge to shut Pitt down.
Remember, Pitt only ran about 60 plays in that game and ND ran more than 100. ND had 34 first downs to Pitt’s 14. They just fumbled three times. Teo made sure the defense held, anyway.
I only watched the last bit, plus the overtimes. I guess that is why I did not find their defense all that impressive.