It is Chelsea's title to lose after they equalled Manchester City's unbeaten record of 31 games and moved top on goal difference with a game in hand.
Yet for all the star quality on display, it was an old-fashioned, route-one goal that decided this pivotal clash.
A long ball from goalkeeper Ann-Katrin Berger found Fran Kirby behind the Manchester United centre backs and the forward kept her cool to chip the ball over Mary Earps and into the net.
Kirby needed just one chance and succeeded where her team-mate Sam Kerr had failed.