The five things you REALLY need to know about the Battle of Old Trafford... as Arsenal get set for huge Man United trip 20 seasons on

Arsenal travel to Old Trafford this weekend to take on Manchester United in what is their next biggest game of a potentially historic season.

Mikel Arteta's side are running out of games if they are to win their first Premier League title since 2004, but must keep winning if they want to oust the seemingly undeniable Manchester City.

Next up is a United side at rock bottom, going into the game on the back of a 4-0 humiliation against Crystal Palace at the start of the week, but with nothing to lose.

Defeat in Manchester would almost certainly spell and end to any title hopes. And Old Trafford isn't an easy place to go - as least historically.

The Gunners will be confident of a result, just like they were 20 years ago. It ended 0-0 that day, but it was a game that has lived long in the memory of one player in particular that played in the game.

VAR would have changed the penalty decision

Mail Sport's Martin Keown is somewhat the poster boy of that day, for better or for worse. Having given away a last-minute penalty, Ruud van Nistelrooy missed from the spot for United, triggering ecstatic scenes from the Arsenal players.

Keown had fouled Diego Forlan late on in the game, and celebrated in Van Nistelrooy's face when he missed the kick. At full time, a number of Gunners players surrounded the Dutchman. All may have been avoided had it been for VAR, however.

The forward was involved in the red card earlier in the game that saw Arsenal's Patrick Vieira sent off for a clash with Van Nistelrooy. It wasn't a situation the away players took too kindly to.

'If you look back at the challenge, I can see that anyone who plays the game, you can see that Van Nistelrooy, when he goes up to challenge, he is leaving all sorts on Patrick,' Keown told Mail Sport earlier this season. 'He's gone in with his leg, he's kicked out, and Patrick has tried to react a little bit, and Van Nistelrooy cowers away as if he's been hit.

'The angle the referee has, you might say it's a good decision. VAR today would just completely wipe that out, it's ridiculous.

'We knew this was a game that was comfortable. We were always concerned about everyone else in the league going there because they had such an aura. Back in those days, you were lucky to get a free kick, never mind a penalty at Old Trafford. It was almost unheard of, it was a really difficult place to go, but for us it wasn't, we loved it. 

'When you look around at the players, World Cup winners, wonderful talents everywhere, they knew head to head they were in trouble, and we knew we were better than them, as good as them. They went onto win the Treble, we won the double.

'We didn’t trust Van Nistelrooy'

On the surface, it appeared hard to understand why the players were so angered by Van Nistlerooy. He had been involved in the red card, but Arsenal players took it a step further.

What followed full time was pushing, shoving, an exchange of some very heated words and a number of players from both teams involved in the melee.

'There was a tremendous rivalry between the two teams but this was about trust,' Keown said. 'We didn't trust Ruud Van Nistelrooy because he was a hugely smart, intelligent player. 

'He would fall over in the penalty box out of nowhere like a pack of cards. He would position himself in an offside position when the ball was being delivered, and when it was switched you had 10 yards to make up on him. Very clever player, ruthless in front of goal.

'He trampled all over me. The little one where you back into the striker and push away to come back, he's stamping all over your feet. We felt we were wronged by him, I was more reactive than proactive. Patrick Vieira paid the price the most, people were trying to light that flame, and I think Van Nistelrooy came after him that day. We were giving it to him, we felt it was going too far.'

United fans outside the house

For Keown, the matter was pretty much over as soon as he left the pitch. Onto the next game. But United fans weren't to forget in a hurry, nor were the media, general fans, or coaches.

Arsene Wenger was forced to defend the defender publicly. Even Keown's wife questioned his antics. United fans took things into their own hands.

'People thought I went below the line, that was a theme of that team,' Keown added. 'We had someone come in to work with us because we were getting players sent off every week. In 2002 we won the league with pretty much 10 men. 

'The enormity of it surprised me. Our photographer said there was someone saying they had an amazing photograph and it made photo of the year. A certain newspaper were asking me to have my photo taken next to it. I wasn't going to.

'It was a strange situation because at the end of the season it all fell away. It wasn't in our mind, we had underachieved. We should have won the FA Cup, we should have won the Champions League. Everywhere I put the TV on, it was on. Even in the House of Lords they were discussing it, how I should be banned for six months. How was I going to escape it?

'I had graffiti outside my house. I didn't know anyone knew where I lived, it was in a little village on the edge of Oxford. All of a sudden I have United fans on my doorstep.

'My wife said, "I think you've gone and done it now". But it was kind of playground stuff. People tried to push me to say In regretted it. I made my decisions based on what I knew then, so I don't really regret anything.'

Inside the Arsenal dressing room

Wenger did back his player publicly, but what did he really think?

He had seen his team act like men possessed at full time, targeting one player.

'The way it worked with Arsene Wenger is he created an environment where you went to him if you thought you had overstepped the mark,' Keown said. 'He didn't need to come to me. 

'A couple of days later, I went to him and said it wasn't ideal, he said, "Yes Martin, but we will sort it out", so we did. It wasn't like a parent in your ear. I didn't do management but you are the ultimate role model and that's how it was with Arsene Wenger. 

'He didn't have to tell me, I knew it wasn't ideal. But it was about passion, spirit, and that we would not be denied again, because Manchester United seemed to keep getting in the way and it was always this particular player that seemed to be causing us a problem. And it didn't work, we went onto go unbeaten, but that team should have done the Treble.'

Arsenal would go on to win the league in what would become the famous Invincibles season. 15 points ahead of United, who were pretty much serial winners.

'It was buoyant after,' Keown added. 'If you went to Old Trafford and got a draw or won you knew you were in the running.

'If that [penalty] had gone in, I would have got the blame. We are in a blame situation and people would have pointed at me and said I gave away a penalty. It was really important for me that that penalty was missed.

'It was changing where the young boys were starting to become leaders. A dressing room with responsibility. There is a demand, you can see it in their eyes, we were reaching that stage. Thierry Henry was almost unplayable in that period. He went into this incredible period, I didn't want to let these people down.'

Out to stop Fergie 

At the top of the United tree, the man leading the troops, was Sir Alex Ferguson.

'Fergie time' is a phrase many will be familiar with. A tongue-in-cheek saying that suggested games would be played until the Scot's sides scored.

There have, in the past, been suggestions of referees being intimidated at Old Trafford. Not on Keown's watch.

'I tried to keep the referee away in 1999,' he said. 'What I saw at half time was shocking, he went after the ref. I thought, "That ain't happening again". I moved him away, I wasn't being physical, I just wanted him to stop. I felt the referee was a bit intimidated in that second half. 

'I looked for it every time we went to play them, see if he was hanging around. I wasn't going to rush into the dressing room.'

What REALLY happened at the Battle of Old Trafford: Watch on Mail Sport YouTube