A request for me back in 2015 by José Ramiro of Sweetie Belle boxing Silver Spoon with Rarity and Rainbow Dash as the referees.

Note: Rainbow is also a referee because Rarity on her own would be too biased.

This is PRIOR to Crusaders of the Lost Mark where Sweetie gets her cutie mark and Diamond Tiara and Silver Spoon are redeemed but given that Silver isn't being bossed around by Diamond this shows some early sportsfillyship from her.