After eliminating opponent w/<5 spoils can a set be played?

I can't find this rule anywhere.
Scenario: you eliminate an opponent and end up with four spoils that includes a set.
Question: During that same turn, can you play that set? or must you have at least five cards?
Scenario: you eliminate an opponent and end up with four spoils that includes a set.
Question: During that same turn, can you play that set? or must you have at least five cards?