Katie Zelem opened the scoring from the spot after 12 minutes when Lauren James was brought down inside the area. Just before the break, United doubled the advantage as Kirsty Hanson curled in a right-footed shot over Blades goalkeeper Nicola Hobbs.
Reds substitute Lizzie Arnot ensured the points were safe midway through the second half, when slotting home from close range after some strong work by Hanson.
Following the recent 12-0 away trouncing of Aston Villa, expectations were high as Stoney’s side arrived at Leigh Sports Village for United’s first home league match of the campaign and the hosts did indeed start brightly.