An equaliser from the last hit of the game saw Spalding ladies first team share six goals with Royston.
They led 2-0 and regained the advantage, only to drop points from a short corner.
Looking to bounce back from a defeat, Spalding soon settled.
Pressure turned into goals as they took control.
Charlotte Maplethorpe turned the last defender and was put in on goal, unselfishly laying the ball off to Lottie Boreham to flick home from close range.
Evie Maltby forced a short corner which saw Kelly Slater, Karen Timby and Boreham combine for Slater to slot home from close range at the back post.
Royston struck back with a breakaway goal before half-time and then levelled in the second period.
Boreham made it 3-2 but Royston scored again from the last hit of the game.
Meanwhile, the men’s first team lost 4-3 at home to Ipswich and East Suffolk in the promotion battle.
Spalding twice went ahead during the first half through Harry Vickers and Glenn Richardson then Stuart Cunnington made it 3-1.
The game looked to be over but Spalding gifted the win as they gave away a number of short corners.