Seven days after claiming Britain's third gold in the space of 45 minutes on 'Super Saturday' in the 10,000m, Farah produced another brilliant performance to complete the long-distance double.
Roared on by a capacity 80,000-strong crowd, Farah hit the front with 700m remaining and was never headed, covering the last lap in under 53 seconds to hold off Ethiopia's Dejen Gebremeskel to win in 13:41.66. Thomas Longosiwa of Kenya claimed bronze.
Farah's victory also meant Britain have won four track and field gold medals for only the third time since the Second World War, matching the haul from Tokyo 1964 and Moscow 1980.
After the race, Farah said simply: 'Its unbelievable.
'I am just amazed - two gold medals, who would have thought that?
'It's been a long journey grafting and grafting, but anything is possible.'