Here's everything you need to know about the new competition.
The first-ever UEFA Nations League champion will be crowned on Sunday, June 9 after nine months of play in the competitions inaugural season.
The group stage of the 2018-2019 tournament ended on Nov. 20, and after two semi-finals games last week, Portugal and the Netherlands will have a chance to become the first team to come out of the UEFA Nationals League on top.
Here's a guide for all you need to know heading into the final.
What is the UEFA Nations League?
The UEFA Nations League is a competition between the 55 member nations of UEFA. The first tournament began in September 2018 following the 2018 FIFA World Cup. The contest was created because UEFA felt that "friendly matches are not providing adequate competition for national teams."
How does UEFA Nations League work?
The 55 nations are split into four "Leagues." The strongest nations are in League A, and the weakest in League D. League A and B are comprised of four groups of three nations (12 teams). League C has three groups of four nations, and one group of three (15), while League D contains four groups of four nations (16). Teams within each group play each other home and away.
The winners of each group in Leagues B, C and D move up, while the nations in the boom of Leagues A, B and C drop down for the next edition of the contest. Because Group 1 of League C only has three teams in it, while Groups 2, 3 and 4 each have four, the nation that finishes bottom of Group 1 is not automatically relegated. The third-place team across all four groups with the worst record are. Therefore, results against the fourth-place team are removed for Groups 2-4.
The four winners from League A will play in a knockout format. This year, those four teams were England, Portugal, Sweden and Switzerland. Only nations in League A can go on to be the overall Nations Lague champions.
The UEFA Nations League finals is a standalone competition. The result does not carry an automatic place at Euro 2020, though Nations League does decide each nation's ranking for the Euro 2020 qualifying draw.
When is the UEFA Nations League final?
This year's final between Portugal and the Netherlands will take place on Sunday, June 9 at 2:45 p.m.