It's arguably the biggest match in the club's history as they take the field at this stage of the women's game's most prestigious competition for the first time in 20 years and face Women's Super League opposition for the first time in competitive action.
Notts County are highly-fancied to do well in WSL1 and have a host of internationals at their disposal - they had five players in the England squad that won the Cyprus Cup last week.
But Spurs, unbeaten so far in 2015, travel to Meadow Lane in fine form.
Below: Karen, Sophie McLean and Lucia Leon preview the tie at Notts County
They moved up to fourth in the FA Women's Premier League South with a 3-0 win against Plymouth on Sunday and manager Karen said the players travel with belief.
"It's one of, if not the biggest game in the club's history," said Karen, a FA Women's Cup winner during her playing days at Charlton.
"We know that the players will have to collectively have the games of their lives but we go there with confidence and believing that we've players who cause them problems as well.
"It's a special competition, we've had a fantastic run to get this far and it's now all about going out there and expressing ourselves.
"It's the first time we've played a Women's Super League team as well and it's exciting times for us with a cup final to come (Ryman Cup Final, April 16) and doing well in the league. I know the players will give everything."