They made it five out of five in competitive action thanks to a 1-0 win in the preliminary round of the competition at Ware FC.
They now face a trip to Sheffield FC Ladies - currently second in the Northern Division - in the first round on Sunday, October 12.
Katie O'Leary scored the only goal of the game in the 11th minute but after missing chances, manager Karen Hills admitted it was a nervous last 15 minutes against the team from Northern Division One.
Karen takes up the story of the game. "We made a few changes with Andra Marcoci, Katie O'Leary and Sophie McLean all coming into the starting line-up.
"We started on the front foot and really took the game to Tranmere with Avilla Bergin and Sophie showing excellent link play down the right.
"The goal came on 11 minutes when Fran Gamble played in Avilla down the right, she beat her defender and delivered a cross that Katie took in her stride and slotted into the bottom corner.
"Katie was denied another goal by the goalkeeper and for the rest of the half, Tranmere frustrated us going forward and almost got a goal back we were penalised for a back pass but our defensive wall did the job to block the free-kick from 10 yards out.
"The second half followed a similar pattern, we continued to dominate possession in the final third but couldn't find a way through.
"As the half went on, Tranmere grew in confidence and it ended up a tense final 15 minutes but we held on to go into the next round.
"Overall, we made hard work of it. You have to give credit to Tranmere, they came with a game plan, defended well and at 1-0, there is always that threat that they could get back into the game.
"Our decision-making in the final third needed to be better and we weren't as clinical as we have been in recent weeks.
"Having said that, a win's a win and we're all pleased be in the next round."
Spurs Ladies vs Tranmere: Toni-Anne Wayne, Sophie McLean, Fran Gamble, Leah Rawle, Jenna Schillaci, Shannon Maloney, Wendy Martin, Katie O'Leary, Lucia Leon (Maya Vio, 65), Andra Marcoci (Natalie Grafton, 60), Avilla Bergin. Unused sub: Leanne Mabey.