CREATE TABLE table_name_54 (opponent VARCHAR2, res VARCHAR2, event VARCHAR2)

Who was the fight against when loss was the result at the Gladiator Challenge 87: Collision Course event?
SELECT opponent FROM table_name_54 WHERE res = "loss" AND event = "gladiator challenge 87: collision course"
SELECT "opponent" FROM "table_name_54" WHERE "event" = "gladiator challenge 87: collision course" AND "loss" = "res"