After being introduced as part of a double change with fellow Red Alessia Russo on 55 minutes, Toone put the Lionesses into the lead with a wonderful chip shortly after, before Lina Magull tied the game with just 11 minutes to go.
United's Mary Earps made several important stops across the 90 minutes before the contest went to extra-time. Sarina Wiegman's side continued to battle valiantly and got the reward 10 minutes from time, as Manchester City's Chloe Kelly prodded home to clinch a historic victory at Wembley for the competition hosts.
Ella Toone!