The Londoners were only seven matches into that record-breaking run when they travelled to Old Trafford last September.

An incendiary 90 minutes ended with Arsenal captain Patrick Vieira sent off and United striker Ruud van Nistelrooy the focus of a baying mob of Arsenal players. Four were subsequently banned.

Rivalry between England's top two clubs has been intense ever since Arsene Wenger arrived at Highbury in 1996 and began building Arsenal into serious opponents for Alex Ferguson's all-conquering United.

Off the pitch, Ferguson and Wenger are like chalk and cheese, with the fiery Scot from Glasgow cutting a sharp contrast with an urbane, trilingual Frenchman who holds a university degree in economics.

Relations were not helped when Arsenal wrested United's league title from them with a 1-0 victory at Old Trafford in May 2002. Ferguson's men responded by snatching it back the following season with a barnstorming finish.

Constant sniping between the sides and their coaches built to a climax last September when the post-match melee led to the four Arsenal players being banned, their club getting fined 175,000 pounds ($316,600) and their manager facing a wave of criticism for his team's poor disciplinary record.

Ironically, for all the damage done, the 0-0 draw proved to be the turning point in Arsenal's title-winning season.

Van Nistelrooy's missed spot-kick kept Arsenal on a record unbeaten run which will reach 50 if they avoid defeat on Sunday.

The ugly scenes also forced Arsenal into a long-overdue look at their behaviour on the pitch.

Wenger's team have picked up only one red card in the Premier League since - Ashley Cole's dismissal against Leicester City in December being the only blemish.

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"I feel it was the turning-point," Wenger told reporters in March as his team cantered towards the title. "With them missing the penalty in the last minute, us not losing and then having to deal with all the incidents.

"We dealt well with the situation. We came out and said we were sorry and it's not how we want to behave. And since that, we've focused purely on football.

"You have to choose -- are you focused on fighting or on football?"

United got their revenge for what smacked of a defeat by knocking holders Arsenal out of the FA Cup semi-finals the following April and going on to triumph in Cardiff.

Victory for Ferguson also denied Arsenal a golden opportunity -- against second division Millwall -- to make history by becoming the first club in over a century to lift the trophy three years on the trot.

Ferguson has already begun winding up his men for Sunday's battle with the league leaders, describing it as a "must-win" game within minutes of Saturday's 0-0 draw with Birmingham City.

He was then quoted as telling Sunday's Observer newspaper that Arsenal "got away with murder" in last season's fixture.

"The disciplinary treatment was ridiculous when you think that Eric Cantona got nine months for attacking a supporter," he added, referring to the former United forward's assault in 1995.

Central defender Rio Ferdinand and skipper Roy Keane were spared Tuesday's Champions League game at Sparta Prague, due to family bereavement and influenza respectively.

With a struggling United already 11 points adrift of their opponents after nine games, Ferguson clearly wants all his key men fit for a game they can ill-afford to lose.

"Showing great desire will be important next week," the Scot said. On past evidence, he is unlikely to be disappointed.