The competitive rank directly below Champion in Rocket League is Diamond. The rank ladder places Diamond immediately before Champion, followed by Grand Champion and then Supersonic Legend.
Diamond is divided into three tiers—Diamond I, Diamond II, and Diamond III—and each tier has four divisions. Players therefore progress through multiple Diamond subdivisions before reaching Champion I. The same tier-and-division structure applies across the other major competitive ranks.
The complete progression begins with Bronze, Silver, Gold, Platinum, Diamond, Champion, Grand Champion, and Supersonic Legend, with Unranked representing a player who has not yet received a competitive rank. The exact rating thresholds can vary by playlist and change with competitive-system adjustments, but the order of the named ranks is clear.
A common mistake is to answer Platinum because it is below Diamond, or Grand Champion because it is often discussed alongside Champion. However, the immediately lower named tier is Diamond. Rank is also playlist-specific: a player can have different ranks in modes such as Doubles and Standard.