Really?

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2126092431/42084383?tab=overview

So, my first game Kindred, I rather enjoyed it. Had a fancy 1v3 at the end of the game, etc. Anyways, I got an S rank for this game, and I was super hyped to receive a chest at the end of the game. But I didn't get it. Riot, why can't we get hextech chests with a champion we don't own, especially if we do really well?!