protivnika

In a sentence

• Na utakmici smo pobijedili protivnika.

  In the match, we defeated the opponent.

  The word 'protivnika' here is used in the accusative case to denote the direct object 'the opponent' whom the action (defeated) was directed at.

• Profesor je raspravljao s protivnikom o teškoj temi.

  The professor debated with the opponent about a challenging topic.

  The word 'protivnikom' appears in the instrumental case, indicating that the action of 'debated' involved 'the opponent' as a partner in the action.

• Protivnik u šahu je bio vrlo vješt igrač.

  The opponent in chess was a very skilled player.

  Here, 'Protivnik' is in the nominative case, serving as the subject of the sentence and identifying the one performing an action or described.