In each Tier you progress through the 6 Tier Ranks from Bronze through to Protonium by winning more games of TDM or Battle Arena (excluding custom games, BRAWLs or single-player games) than you lose.
In each Tier you progress through the 6 Tier Ranks from Bronze through to Protonium by winning more games of TDM or Battle Arena (excluding custom games, BRAWLs or single-player games) than you lose.