They take on Wigan Athletic at the Lancashire FA ground in Leyland (7pm) in the Fifth Round - a tie to be live streamed on BluesTV.
The Latics top PDL North - they have won 14 of their last 15 games - and disposed of Spurs in the previous round.
Blues, though, showed what they are about in the Fourth Round, memorably defeating Barnsley 2-1 despite being reduced to nine men.
Both Josh Williams and Josh Andrews, sent-off within 14 second-half minutes of each other against Barnsley, have served three-match bans.
"Wigan are very clever," said Coach Paul Robinson. "They have got some very clever movements in their team and with their players in the forward line. The midfield, as well, is aggressive.
"We expect another tough game. They will look to try and get us on the back foot.
"We need to focus on our game and how we can try and break them down and the things we can hurt them at.
"We will always do our homework on the opposition but the thing is it's about us, how we need to go about it."
Robinson said that the amazing win against Barnsley, courtesy of Kyle Hurst's 87th minute strike, gave the squad a huge spring in their step.
"The fact the lads won the game with nine men shows great character and belief within the group.
"You can see the buzz around the group in training.
"We want the boys to enjoy the football but this competition as well. It's their FA Cup, it's special.
"Yes, the buzz, the belief, the feeling from the last Cup tie, they have been taking it into the league definitely."
In fact the Under-18s have become a tough nut to crack of late - they are eight unbeaten in league and cup.
With just Kade Craig (thigh) not available, Robinson has various permutations to consider.
Nico Gordon, the captain, was in Pep Clotet's First Team squad as 19th man for the dramatic FA Cup Fourth Round replay against Coventry City last night. Gordon was also in the squad for the Nottingham Forest game.
Combined with the return from injury of Charlie Noakes at centre-half - he has played in the last two PDL matches - it's something to ponder.
Robinson said: "You love the headaches. We want the boys to challenge each other. Yes it makes your job harder but that's fine.
"The worst thing about it is that none of the boys have done anything wrong. It's just about us choosing the team to try and win the game.
"Charlie has come back from a long injury lay-off. It is great to have him in there again. He is a great lad, an enthusiastic character, a voice.
"Nico has been with the first team. That's brilliant. It's what we want. I don't mean that horribly, but you want them to be catching the eye of the Head Coach and being picked in his squad.
"We will wait and make the decisions on what we are going to. We have a strong squad and we have almost everyone available."
Should they figure, both Williams and Andrews will certainly be in the mood to make amends for the red cards against Barnsley.
Robinson reflected on Williams: "We had a chat after the game. One to one. He knows how disappointed I was with him.
"But I felt he was going for the ball. There was no malice in it. It was one of those things. It's learning from it, isn't it? He got a three-game suspension.
"It was a situation whereby he could have thought 'did I really need to go in like that?' knowing that he might not have got the ball.
"Look, I have been in situations like that myself and it's about trying to help him out, pass the experience on to him that if the ball is not there to be won, just stay on your feet or make it easier on yourself by getting into a different position.
"Josh came back in at the weekend at Burnley and he did look rusty, he was a little bit off. But he got the minutes under his belt and we will look at what we do for Wednesday.
"There are players who have played really well since he's been out. So we will decide on that and other things."
Andrews was angered by an elbow to the face that left him with a bloody nose.
"If the referee had seen what their player had done to him before it, it would have been a different matter," said Robinson.
"The referee could have taken both incidents at the same time and given them a talking to, or dished out a yellow card each. He had only seen what Josh did, apparently.
"Josh has learned the hard way, how to control your reaction. He's never usually in that way inclined.
"But his ban is over, so is Josh's, and it's great to have these two back and the threat we know they do pose when they have been available."
The winners of tonight's tie face an away trip in the Quarter-Finals to either Manchester United or Leeds United, who also play this evening.