Goliath
Goliath is described in the biblical Book of Samuel as a Philistine giant defeated by the young David in single combat. The story signified Saul's unfitness to rule, as Saul himself should have fought for the Kingdom of Israel.
Single combat
Duels between individual warriors are depicted in the "Iliad", including those between Menelaus and Paris and later between Achilles and Hector. The Hebrew Bible also includes a few accounts of single combat, the most famous being David versus Goliath.