On 21 September 2003, Arsenal preserved their unbeaten streak by the narrowest of margins, drawing 0-0 after a missed Manchester United penalty.
When the Gunners arrived at Old Trafford, they were enjoying a modest seven-game unbeaten streak that stretched back to the last two matches of the previous season--a season that had ended with United beating Arsenal to the top of the final table after some heated confrontations between the two sides. In February 2003, Arsenal won a heated FA Cup contest over United in a match that saw a slew of yellow cards. Then, in April 2003, the teams played to a draw after Arsenal defender Sol Campbell received a straight red for an elbow to the face of United's Ole Gunnar Solskjær.
Campbell missed the match on 21 September, but the emotions still ran high. The day's first yellow card went to United's Roy Keane in the 21st minute, with seven more to follow. Arsenal captain Patrick Vieira was ejected in the 80th minute after receiving a second yellow for a confrontation with United striker Ruud van Nistelrooy.
In the 91st minute, the referee awarded United a penalty for Martin Keown's challenge on striker Diego Forlan. Van Nistelrooy stepped up to take the kick, despite missing his previous two attempts. True to form, he slammed the ball against the bar, drawing an emotional taunt from Keown.
The match ended as a scoreless draw and Arsenal proceeded to go undefeated for the remainder of the season.