It was a landmark day for football when Millwall and Fulham met on January 20, 1974.
The two London clubs will go head to head on Saturday in the Championship in what will be their first meeting since 1999.
But some 40 years ago the pair met for an historic clash at The Den, which would go on to change the face of football forever.
For it was the first time that a league match was played on a Sunday - something as common these days as enjoying a roast dinner.
The introduction of Sky in the 1990s means settling down to a watch a game on a Sunday is almost second nature, particularly for the younger generation.
But back in 1974 it was a different story.
Britain was in the grip of an energy crisis caused by Arab OPEC members refusing to provide oil to western nations who had supported Israel in the Yom Kippur War in 1973.
At the beginning of 1974 the miners went on strike which exacerbated the situation even further.
With clubs looking to save on energy by not using floodlights, the call came forward for Sunday games to be played.
So step forward Millwall and Fulham who kicked off at 11.30am, one of three Second Division matches played that day.
Brian Clarke scored the only goal of the game as the Lions won 1-0 against a Whites team which featured the likes of Barry Lloyd, Les Barrett, Alan Mullery, John Mitchell and Alan Slough - all of whom would go on to play in the Cottagers' only ever FA Cup final appearance, against West Ham, a little over a year later.
As well as the energy crisis, there was an added problem. Law at that time prevented tickets being sold for a game on Sunday so admission was technically free.
Clubs got round this by making people buy a programme which got them entry into the ground.
And that was that - Sunday league football was born.
A week later the first Division One match was played on a Sunday with Chelsea meeting Stoke.
As for the rest of that 1973-74 season, Fulham went on to finish 13th in the table, one place behind the Lions.
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