United held on with 10 players to win the game 2-1, with all three goals arriving during a nine-minute spell midway through the second half.
Leah Galton smashed home from close range to give the title-chasing Reds the lead, before Beth England replied for the home side with a superb individual effort.
Molly Bartrip's own goal, almost directly after the restart, proved decisive, although there were some nervy moments late on at the Tottenham Hotspur Stadium after Toone's sending off.
Although boss Marc Skinner suggested the club would appeal the decision, Toone had looked set to miss the meeting with Durham, in the Women's FA Cup, and key league clashes with Leicester City and title challengers Chelsea.