Fulham are focused on Sunday's huge challenge against a Lionesses side one point off the top of the second division and eyeing promotion to the Women's Super League.
Fulham are in a promotion race of their own, external. They have won seven and drawn one of their eight league fixtures so far and, although they are 10 points behind leaders Dartford, they have five games in hand following a series of postponements earlier in the campaign.
Defender Becky Stormer, who was in the original Fulham Ladies academy before returning to the club six seasons ago, says they are relishing the unfamiliar role as second favourites and will be well prepared, despite their squad only being able to train three times a week around their full-time jobs.
"Being realistic we are the underdogs, but this is a good place to be," she told BBC Sport. "We wanted a Women's Super League or Championship club, and are super excited for the test.
"It's very different opposition, so this week we have an extra training session and might be changing our tactics a little bit," added midfielder Stella Gandee Morgan.
"Mostly it's excited nervousness. We haven't been the underdog this season so the pressure is all on them.
"We are going in with a lot of confidence. We know if we can hold them, we have people who can score goals."
Fulham came through the preliminaries and have had to win five games before facing London City Lionesses, who entered at round three.
The Whites beat seventh-tier Epsom & Ewell 13-0 in the second round of qualifying before defeating two fourth-division sides and winning 2-1 at neighbours Brentford in round three to set up this tie.
"We have had a really good run, and with the magic of the cup, we will see what happens," striker Ellie Olds – who scored the opener at Brentford – told BBC Sport.
"Our main focus is the league, but to be on this amazing cup run is really cool. It is a free hit, there is no expectation for us to win."