It was a Premiership fixture dubbed the P45 derby in November 2002.
Terry Venables took his Whites side to face Glenn Roeder's Hammers in the capital with both sides struggling for form in the top flight.
United had been used to fighting for places in Europe while the hosts were being handed an early season relegation scare.
A dramatic 4-3 victory for the Elland Road club handed a short term reprieve to Venables in a game littered with defensive mistakes.
Leeds burst into a 4-1 lead at the half-time interval with Upton Park furious as a shocking first half display at the back.
Nick Barmby opened the scoring with a header before two goals from Harry Kewell followed to give the Whites a cushion.
Mark Viduka charged down a clearance to tap into an empty net and leave Paolo Di Canio's earlier effort seemingly irrelevant.
Di Canio struck again five minutes into the second half from the penalty spot after a loose Gary Kelly challenge and Trevor Sinclair had a third for his side 16 minutes from time,
Leeds, though, held on with their backs against the wall to record an important three points to move 10th in a furious game. The Hammers remained in 18th place in the first relegation zone.
Here, we take a look back at who played on that memorable and frantic day and see where they are now...