Arsenal against Manchester United is one of the biggest derbies in the Premier League but in the early noughties, it reached a peak level of competitiveness.
The two giants, led by the likes of Roy Keane, Gary Neville, Patrick Vieira and Sol Campbell were fierce rivals as they jostled for the title. Games were fuelled by competitiveness and there was a lot of bad blood between the two clubs that stemmed from manager Arsene Wenger and Sir Alex Ferguson.
A 0-0 draw at Old Trafford during Arsenal's invincibles season saw the rivalry reach boiling point and produces one of the Premier League's most iconic moments.
Ruud van Nistelrooy missed an injury-time penalty, rattling the ball off the crossbar and was confronted by Martin Keown, who jumped in his face in complete euphoria after the Dutchman's misfortune from 12 yards.
13 years on, Van Nistelrooy is still asked about that afternoon in Manchester. During a Q&A session at the Oxford Union, the subject once again came up.
The former United and Real Madrid joked about what would happen if he saw Keown - who lives in Oxford - then took a dig at the former Gunners defender, saying he thought you had to be smart to live in the city. You can see the video below.
Van Nistelrooy's injury time miss from the spot preserved Arsenal's unbeaten start to the season and the north London club went on to lift the title, going unbeaten.