Villa defender Stephen Warnock knows only too well about the FA Cup’s tendency to throw up shocks.

After all, he has been on the receiving end of one of the biggest in recent times.

Having already booked one Wembley trip to contest the Carling Cup, Villa have the chance to move a step closer to reaching a second final when they take on Brighton in tomorrow’s FA Cup fourth-round clash at Villa Park.

They will kick off hotly-fancied favourites against the League One Seagulls – but Warnock knows only too well that can count for little when you cross the white line in the world’s oldest domestic football competition.

Warnock was in the Liverpool team who suffered one of the previous decade’s most infamous FA Cup shocks when Burnley, then treading water in mid-table of the Championship, claimed their hefty scalp at the third round stage in 2005.

It is particularly memorable for the bizarre own goal scored by Djimi Traore, who attempted an ill-advised Zidane-style turn and drag-back within his own six-yard box – only for the ball to end up in the back of the Reds net.

That January night in Lancashire still rankles with the now-Villa defender, who scored his first claret and blue goal in Wednesday’s extraordinary Carling Cup semi-final win over Blackburn.

Warnock is desperate to avoid going through such a demoralising experience again when Gus Poyet’s unfancied team visit the Second City tomorrow.

He said: “I played against Burnley when I was at Liverpool a couple of years ago and we went out. That was a game that went down in history as one of the big upsets, so I’ve played in games like that where you slip up against a banana skin team.”

With Manchester United and Liverpool already out of the competition, the draw has already begun to open up for Villa even at this early stage.

But, after beating both of those sides and Chelsea already this season, Warnock insists Villa would have still believed in their chances even if those teams had still been in the competition.

He said: “I don’t think it would have mattered in the FA Cup even if the big teams were in it. We are a big team ourselves and we know we’re more than capable of beating the top four – we’ve done it this season so we’ll take anyone.”

O’Neill is expected to ring the changes with the likes of Fabian Delph, Luke Young, Steve Sidwell, Nathan Delfouneso and Nigel Reo-Coker.

If fit, set to come in for the likes of Richard Dunne, Stiliyan Petrov, James Milner, Gabby Agbonlahor and Ashley Young likely to be given a rest following Thursday’s semi-final exploits.

Skipper Petrov believes the Villa boss has the luxury being able to call on quality whoever selected.

The former Celtic man said: “I think everybody here is waiting for their chance. I think everybody who gets the chance will prove that they are worthy of being in the team.

“Everybody’s pushing for a starting place, even if we make changes I don’t think there will be any problem. That’s what makes us better, the competition, we’re pushing each other every day in training and in the games. If we keep doing that it will just make us better as individuals and as a team as well.

“Siddy has done great, what he has been missing is that he’s been very unlucky to not score goals. But he’s been having chances and that will happen.

“He’s a great player. Nigel, Fabian, there’s lots of great players in there. If you take any one of us, they’ll replace each other so there won’t be any problem.”

In the other camp, former Chelsea and Spurs midfielder Poyet admits his Brighton side will still face a mammoth task regardless of what side O’Neill names.

Poyet said: “When you say they will not play a full team you are talking about people like Carew, who was on the bench on Sunday against West Ham.

“Luke Young has been playing in the Premier League for a long time and so have Reo-Coker and Sidwell. We are talking about top players and they are going to be fresh, with the determination to show that they want to be in the first team.

“Any team Aston Villa put out should be better than us. We are going to try to prove that wrong.”

But Poyet believes it will only take two or three claret and blue players to take their eyes off the ball to give his team a chance of an upset.

He said: “It’s the concentration and that strong winning mentality, to play every single game the same way. That helped me personally when I was playing for big teams against a lower division team.

“But we are all different. People think that is the manager’s role, but only the players know what is going through their heads.

“It is down to the individual. If you have two or three who are not ready for this kind of game then the whole team has a problem.”

It promises to be a dream afternoon for Seagulls midfielder Andrew Whing, who holds a season ticket at Villa Park alongside his father.

He said: “It’s quite funny and surreal actually. I never thought it would ever happen to be honest. If I am involved it will be fantastic, strange to be rubbing shoulders with them rather than sitting in the stand watching them.

“It’ll be a strange experience but all the lads are looking forward to it, and it’s a great for the supporters as well who’ll travel up there.”