Rangers parted ways with manager Jody Banim in the week with Matty Hill taking over on an interim basis with support from Paul Hayward.
The new management team got their era off to a perfect start with Joe Cuff flashing a shot wide early on before putting his side ahead after Callum Coyle played him in.
The hosts soon responded with Michael Gyasi flashing a shot wide before Jacob Ballinger sent his effort into the side netting.
Town striker Dylan Williams then forced goalkeeper Lewis King into action to keep the visitors ahead at the break.
King was also forced into action during the second half denying Ben Seymour-Shove, Gyasi and Michael Harding.
However, with a minute left on the clock Sam Coulson was judged to have fouled inside the box and Williams equalised from the penalty spot.
On penalties St Ives Town were clinical and secured their place in the next round.