pojedynek in English:

His son had been killed in a duel.

D'Artagnan challenged the three Musketeers to a duel.

a duel to the death

Kyouichi Saionji, who he supposed would win the duel, has lost.

After the second innings, the opposing pitcher recovered too, and it turned into a pitching duel.

Dad, this a real sword? "Of course, it is a duel after all."

Surrounded by hordes of vampires, Christopher Columbus once had an epic sword duel with Count Dracula in the latter's castle. After the Count cut off Columbus's hand, Columbus calmly picked it up, put it back in place, and proceeded to best the Count.