What ensued was a brutal hour-long battle leaving both animals bloodied, exhausted and with fatal wounds.
The feline is tossed around in the air as he attempts to mount his adversary and is finally finished off when another buffalo arrives on the scene to deliver a lethal blow.
The amateur photographer, from Eastbourne, who works for Shenton Safaris as a guide and camp manager, came across the bloody scene as the lion’s claws were hooked into the female buffalo’s muzzle.
He recognised the cat as a six-year-old lion who suffered from mange, a type of skin disease, and who had become detached from his pride.
Mr Armstrong said: ‘After around ten minutes of our arrival the buffalo managed to shake the lion off itself but instead of trying to escape just stood there.
‘Both animals stared at each other both too exhausted to move.
‘After a few minutes of rest the lion then went for the buffalo and another ten-minute battle ensued. Again the buffalo managed to shake itself free.
‘The same process continued for about an hour until both animals were completely spent.
‘The rest of the herd, who had come to the water to drink were watching from a distance while the fight carried on.’
The safari guide added: ‘That seemed to give the cow the opportunity it needed to escape and along with the rest of the herd moved off.
‘After this the lion managed to drag himself under a bush to lick his wounds. Both animals were covered in blood by the end.’
Mr Armstrong added: ‘I have never seen anything like that before. Usually when lion hunt buffalo it is as a pride – it is hardly ever alone.
‘The fact that the lion was familiar to us and we had seen him in his prime made it very emotional to see him in the state he was in. By the end of the fight everyone was exhausted.’
All these amazing pictures are courtesy of Matt Armstrong-Ford