The Bournemouth-based side travelled to Reading to take on third-placed Barton Rovers, with all three points required to oust the leaders, due to a waker goal-difference.
Although Olivia Jones put New Milton ahead, Phoebe Cole levelled by half time, to set up a tense second period.
With 8 minutes left, Jones – the division’s top scorer – made it 20 goals from 18 games to clinch the win and the Southern League Division 1 title.