Hemp, 23, was slotted through perfectly by Park in the 27th minute, as her first-time left footed effort squeezed past Sophie Baggaley in the Brighton goal to give City the lead away from home. Her eighth goal of the Women's Super League season so far.
Mary Fowler would go on to add a second for the visitors just before the break, before Khadija Shaw and Laura Coombs also got on the scoresheet in the second half.