Czech Republic's Kuncova overcame Cerna 6-2 at the Royal Artillery Barracks.
'It was really unpleasant because we were facing each other. I was a bit nervous - it was my first time on the shooting range, which is set up a bit differently (to what she is used to),' said Kuncova.
'We are sharing a room so there are no bad feelings – we will remain friends.'
Cerna said: 'I was a bit nervous in the beginning, but my ambition wasn't high. I had poor form during the spring so I wasn't hoping to get very far.'
In the men's Individual Recurve - W1/W2, Czech Republic's Taras Chopyk defeated Italy's Vittorio Bartoli 7-3.
Chopyk said: 'The first two series of arrows were normal, the second two I became nervous, but I go to the next round. It is important to take courage in both your hands.'