There was a time when Arsenal fans would be sh**ting themselves about going to Old Trafford.

It’s not hard to remember, it was only last season. And the one before that. And the one before that. Four wins at the home of the Red Devils this century explains much of why that might be, but it’s always been about more than just the result on the pitch when Arsenal and United play each other.

Before Sunday, United fans were convinced that, no matter what has happened to them since Sir Alex Ferguson retired, they could be guaranteed to turn Arsenal over, especially at home. I don’t blame them, many Arsenal fans feared the exact same until they saw Tottenham turn up at the Emirates and get their arses handed to them.

If I was a United fan I’d be looking forward to the arrival of Arsenal because I’d know that no matter how bad we were playing, Arsenal will just bend over and grab their ankles as we grab the points.

I’m sure there has been a lot of rethinking going on since Sunday, if not in the head of United fans, then certainly in the head of Arsenal’s. It’s rare that Arsenal fans can look forward to playing a Jose Mourinho side, but that’s exactly where we find ourselves – itching for kick-off so we can turn the screw on one of football’s most pathetic pantomime villains.

During the game against Spurs on Sunday Gary Neville remarked that there was ‘no way’ that Arsenal could keep up the intensity with which they battered Spurs for the first 20 minutes. He was wrong. Anyone thinking that they cannot follow up that Spurs spanking by doing the same three days later at Old Trafford would be mistaken.

Arsenal will arrive at Old Trafford on Wednesday determined to show that the performance and result against Mauricio ‘won nothing’’ Pochettino’s side was not just a one-off but a new page in an exciting new book, tentatively called ‘How not to be dicks when playing football’.

Unai Emery has overseen a 26-point swing between Arsenal and United when you compare this season to last, although Jose has certainly played his part. United are so bad that they’ve banned Juan Mata from writing his blog, lest it be a distraction from the serious business of going two-nil down to a side managed (not any more) by Mark Hughes.

Whatever Mourinho is doing at United just isn’t working, and while many points could be made about how their problems run much deeper than just the manager, he is the focal point for every Arsenal fan this week.

This is a man who has heaped humiliation upon indignity on Arsenal and as his star fades to a level of brightness even David Moyes would struggle to see, Gooners want to be the ones to snuff it out entirely.

Can they do it? There’s absolutely no reason to think they can’t do to United what they did to Spurs, other than history and our own fears. Latter-era Wenger teams were polite and pleasant, they went out of their way not to offend.

Ask Eric Dier about Unai Emery’s Arsenal.

Spurs turned up at the Emirates expecting more of the same from Arsenal and if there can be said to be any sort of downside from Sunday’s result, it’s that United are now forewarned.

It won’t matter.

Jose’s time has come and Unai Emery is about to deliver the sweetest gifts of all to Arsene Wenger for the talent he left for the Spaniard to utilise – Jose Mourinho’s crying head on a gilded platter.

This article was first written for Paddy Power.