The NCAA Baseball regional round is one of the most punishing in college sports. Because of the quirky nature of baseball, you have to lose twice in order to advance to a best-of-three super regional series. Thus, you inevitably have to beat a team twice in order to advance, and if you lose at any point your pitching depth is tested more than it is at any other point in the season, including the College World Series.
Thus, once the Tar Heels lost in controversial fashion on Saturday night, they were facing a three-games-in-two-days set in order to advance out of their home regional.