It was a perfect close up of one of nature’s most magnificent beasts... except for the clenched fist speeding towards the camera.
But this powerful right hook is what happens when you start a fight with the king of the swingers by invading his space.
The gorilla – intoxicated by a diet of fermenting bamboo stems – spotted Christophe Courteau’s lens pointing right at him.
Result: 6ft 6in of 200 kilogramme gorilla came charging towards the camera – and produced this spectacular close-up.
There could be only one winner.
Akarevuro the Rwandan silverback thwacked the 46-year-old wildlife photographer effortlessly to the ground.
The contest was captured on camera during a visit to the Kwitonda gorilla group in the forest area of Volcanoes National Park, Rwanda.
Christophe Vasselin photographed the aftermath as Akarevuro trampled over his colleague.
‘Akarevuro just ran at me,’ said Mr Courteau. ‘I could not move away because I was taking photos on my knees.
'In less than a second he was on me. He pushed me out of the way as if I was not there.
'I felt all of his power and weight on my body. It was like being hit by a train.’
Mr Courteau escaped with ‘a souvenir scar on my forehead’ and ‘an instant I will remember all my life’.