Trailing 37-36 with 14:07 left to play, Robert Morris scored 13 unanswered points, capped by McFadden's layup to go ahead 49-37 with 9:04 remaining.
Shane Gibson's layup with 1:27 left cut Robert Morris' lead to three, 62-59, but the Colonials made four free throws in the final minute while the Pioneers converted just one field goal to seal the victory.
Robert Morris shot just 34.6 percent (9 of 26) in the second half but made 18 free throws in the period compared to Sacred Heart's 11.
Gibson led the Pioneers (5-11, 3-2) with 27 points and six rebounds.
Florida State's student government has passed a resolution discouraging Seminoles fans from wearing Native American headdresses at games.
The second annual Gavitt Tipoff Games, eight games between members of the Big East and Big Ten to be played Nov. 14-18, will feature Villanova at Purdue in the opener.
Michael Lewis is leaving his assistant coaching job at Butler to take the same position at Nebraska under Tim Miles.