Mainstage 2021 is an upcoming Super Smash Bros. Melee and Super Smash Bros. Ultimate national tournament held in Ontario, California, from November 12th-14th, 2021. This is Beyond the Summit's second Smash tournament that they hosted and is not a Smash Summit tournament. The top 6 non-invited players for Melee will qualify for Smash Summit 12 and players for Ultimate will also qualify for Smash Ultimate Summit 4.
Super Smash Bros. Melee singles
Super Smash Bros. Melee doubles
Super Smash Bros. Ultimate singles
Super Smash Bros. Ultimate doubles