The win is the second ever for the Orange (13-1, 5-1 Atlantic Coast Conference) against the top team in the nation and ties Syracuse with the Tar Heels (12-2, 5-1) for first place in the conference.
The Orange beat then-No. 1 Florida, 14-13, in double overtime in the semifinals of the 2012 NCAA tournament.
"I thought our players performed excellent against the No. 1 team in the country," Syracuse coach Gary Gait said. "A couple of keys for the game were our possession and the few turnovers we had. We talked about it a lot this year — unforced errors — and today we didn't make them."
Mikaela Rix had five goals and an assist for Boston College.
Penn led 6-1 at the break.
Marlee Paton led Loyola with a game-high seven points on four goals and three assists, while Annie Thomas (John Carroll) had three goals and three assists.
No. 20 Navy 8, Holy Cross 6: The Mids' Aimee Gennaro scored the go-ahead goal to make the score 7-6 with 19:56 left in the game, and Kaitlan Moynihan added an insurance goal with 5:16 left as host Navy (14-1, 6-1 Patriot) beat the Crusaders (5-11, 3-4).
UMBC 12, Vermont 9: Kristen Bilney (Mount Hebron) had her fifth hat trick of the season and the host Retrievers (7-6, 1-2 America East) beat the Catamounts (10-4, 1-2).