Rooney was left out cold after Bardsley caught him with a left jab as they went toe-to-toe in his kitchen.
The 29-year-old is seen falling to the floor and appears to hit his head with a thud as he lands heavily on the ground.
He was left apparently out cold, arms splayed to the side and his head partially under a dining room chair.
As he lay unconscious, shocked friends rushed over before filming came to an end.
The footage will doubtless infuriate England manager Roy Hodgson and others in the Football Association’s hierarchy.
The tussle could have left Rooney with serious injuries and is unlikely to have impressed his bosses at Manchester United, which pays him a salary of £300,000 a week.
Rooney, capped 101 times by his country, and Bardsley, 29, were team-mates at United between 2003 and 2008, before Bardsley left Old Trafford for Sunderland and then Stoke City.
The video, obtained by The Sun, shows the pair bump boxing gloves - Rooney’s white and Bardsley’s pink - before a friend calls “ding ding” for the bout to begin, Rooney wearing socks on the tiled floor
With music playing in the background, the pair circle each and trade punches next to a dining table and a cabinet holding bottles and photograph frames, ducking and weaving as they hold their hands up to guard their faces.
After Rooney throws two left jabs and a right punch the “fight” intensifies. As Bardsley steps in and the pair start grappling a voice calls “whoa, whoa” in an attempt to cool things down.
They push each other away and grapple again, throwing heavier punches at each other, Rooney landing a good left hook on Bardsley’s jaw.
But after breaking apart again Rooney holds his left arm out straight, only for Bardsley to catch him with a clean left punch as they circle each other again.
Rooney’s head rocks back, his feet go out from under him and he lands with a thud. A voice shouts “ooohhh”, before there is nervous laughter as the England captain lies out cold on his floor and the footage ends.
The Sun said the incident happened on February 22, when it claimed Rooney’s wife Coleen was away on holiday with their two sons.
Rooney’s spokesman declined to make any comment.