It was a great accomplishment by Izzy to break Tony's 303 yard rushing performance. However, Dorsett's performance is much more impressive based on who Pitt played. Notre Dame had three number one picks on defense (Niehaus, Browner, Bradley) and two number two picks (Golic and Fry).
He also added 71 receiving yards as well. That game turned the fortunes of Pitt overnight.
The thing I will always remember about Dorsett was in his senior season (1976) When Pitt's first two starting QB’s (Haygood & Cavanaugh) went down with injuries, every school in America knew they only had to stop Dorsett to beat the Panthers and spoil their National Championship run. Dorsett responded with 650 yards rushing in the 3 games Cavanaugh was out (average of 216 yards per game). That is greatness.