The Nittany Lions fell short during a marathon shootout in their trip to the Frozen Confines.
Mack was considered one of the Nittany Lions' best rising prospects after his one year in Happy Valley.
The Nittany Lions are 0-2 as underdogs this season.
The game featured 14 lead changes and 11 ties.
The Nittany Lions most recently beat the Fighting Irish 31-10 in the first full Beaver Stadium White Out.
"I'm a believer. I wasn't a believer in Penn State early on. I'm a believer right now."