This is the 14188th most frequent Turkish word.
müzakereyi
"Negotiation" or "discussion."
In this sentence, 'müzakereyi' refers to the specific negotiation that the subject participated in and won. It is used as an object of the verb 'kazandı' which means 'won'.
Müzakereyi kazandığına sevindi.
He was happy that he won the negotiation.
Here, 'müzakereyi' is the object of the action of wanting ('istediler'). It refers to a particular negotiation that the subject intended to be brief.
Müzakereyi kısa tutmak istediler.
They wanted to keep the negotiation brief.
In this context, 'müzakereyi' is the object of the verb 'yapmak' (to do/make). It conveys the intended action of carrying out the negotiation.