The 16-year-old forward scored nine points (eight goals, one assists) to be named Clark Cup Playoffs MVP. He scored five points (four goals, one assist) in the Clark Cup Final.
Sean Farrell had two assists, and Simon Latkoczy made 27 saves for the Steel, who won their second Clark Cup. Chicago defeated the Sioux City Musketeers 3-2 in 2017.
The Steel are the first team since the 2012-13 Dubuque Fighting Saints to win the regular-season Anderson Cup and Clark Cup in the same season. Chicago won the Anderson Cup during the 2019-20 season, which was cut short because of the COVID-19 pandemic.
Cody Monds scored, and Andrew Miller made 29 saves for Fargo, which won the Clark Cup in 2018.
Fantilli (2023 NHL Draft) ripped a wrist shot from the right face-off circle for a 1-0 Steel lead at 11:08 of the first period.
Monds tied it 1-1 at 12:40 when he scored from the bottom of right circle between Latkoczy's five-hole.
Jackson Blake (2021 NHL Draft/North Dakota) made it 2-1 at 13:17 of the second period when he scored on a rebound from Adam Robbins' (Princeton) shot.
Farrell (2020 fourth/Montreal Canadiens/Harvard) skated behind the net then sent a pass to the back post for Fantilli, who scored his second of the game at 17:55 of the third period.
Chicago's Matt Coronato (2021 NHL Draft/Harvard) scored 13 points (nine goals, four assists) in eight playoffs games to lead the USHL.