It will be only the fourth Manchester derby in the WSL but Friday night's showdown at City's Academy stadium is set to be the biggest we have seen so far.
Chelsea were the overwhelming favourites to win the league after beating United last month but their shock defeat by Brighton last weekend saw the title race blown wide open.
The Blues recovered to beat Arsenal 3-0 on Wednesday, putting the pressure back on the two Manchester clubs. Chelsea have 35 points from 14 games while United are second with 32.