Clayton, who made 8 of 10 shots, scored 10 points during a 23-0 run by Florida State (10-1) after the Spartans (3-7) had taken an early 9-7 lead.
The Seminoles led 55-22 by halftime, holding UNC Greensboro to 26.7 percent shooting (8 of 30) while making 47.8 percent (22 of 46) themselves.
UNC Greensboro actually outscored Florida State 41-38 in the second half, making 9 of 16 from 3-point range (56.3 percent) against a Seminoles team that had been holding opponents to 21.8 percent on 3-pointers coming into the game.
Lucy Mason scored 17 of her 21 points for the Spartans in the second half, making 5 of 7 treys.
Alex Deluzio contributed 12 points for Florida State, Natasha Howard and Leonor Rodriguez scored 11 each and Chelsea Davis added 10.