Marc Skinner's side were ruthless in front of goal against the Royals, scoring all four of their goals in the first 45 minutes.
Maya Le Tissier celebrated her debut with two goals, both from corners, and also helped the backline keep a valuable clean sheet.
Skipper Katie Zelem marked her 100th United appearance with a goal from the spot and registered two assists from set-pieces, while Alessia Russo applied the finishing touches to a perfect first half with a thunderous header beyond Grace Moloney between the sticks.
A FRUITFUL FIRST HALF
It was goals galore in the opening 45 for United.