Gangplank skin

"TLDR: Bilgewater: Burning Tides sails away on August 10 at 2:00 AM PDT. You can earn the free Captain Gangplank skin if you own the champion and play a full matchmade game with him (or if you’ve already played at least one) before the event ends."

what exactly is a full matchmade game?

Can i teambuilder/brawler/ranked/dominion/3v3/ARAM/draft/bots to earn it?

Or do i have to play a draft style game where i have to argue with teammates to get the position and champ i want?