Just to clarify, this has to be 20 games within the same type of mode, not just 20 total games in Ultimate Team, e.g. 20 games in Single Player Seasons, Division Rivals, Squad Battles etc.
It won’t unlock if you play 19 Single Player Season games and 1 Team of the Week game, or any other combination.
This will probably come with natural progression for the most part anyway but thought I’d just make it clear.