Larkin was impressive all afternoon, but it was her goal on the 76th minute that made all the difference in South London.
Palace broke with pace - Annabel Blanchard releasing Ashleigh Weerden on the left-wing.
Weerden hesistated for a second and lofted a ball to the back post where Larkin was waiting to head beyond Sophie Whitehouse.
It was a goal assisted by the league's leading assist-maker, and scored by the league's joint top scorer.