Rematch is a feature added to the Spirit List in version 8.0.0 of Super Smash Bros. Ultimate. It allows any Spirit with a Spirit Battle to be rematched at any time. Unlocking the Spirit the first time will allow them to be viewed in the Spirit List, where they can be rematched as many times as one desires. Spirits that can be fought have a red label with the Spirits logo on it. While highlighting the Spirit, the player can press either X or + to be taken to a rematch of the Spirit. The rematch battles are set up as if they were on the Spirit Board, including allowing the usage of Support Items. Any Spirit with a battle can be rematched in this mode, even those whose battles are not normally accessible through the Spirit Board (for example, Master Spirits whose battles are normally exclusive to Adventure Mode: World of Light).
After beating the Spirit in the battle, the player will gain a high score, some Spirit points, some experience, and the Spirit icon will be darkened. This however, will not award additional copies of the Spirit, Gold, Snacks, or any Support Items. Once those are obtained, a score is seen in the top right of the screen under the number of Spirits obtained that accumulates with every Spirit battle won.
The score and amount of SP earned can be determined by the Spirit team used, with the primary Spirit's power determining SP gained and team power determining the score. The highest score that can be obtained is 100 times the opponent's battle power and the lowest score is the opponent's battle power. Similar to collecting every Spirit, there is no special reward or congratulations screen for clearing or getting the max score for every rematch.
The formula for the score gained is floor(b × (0.16r² - 0.8r + 1) × i) × 100, where r is less than or equal to 2.25.
An r of 0 (i.e. no Spirit team) will give a score of b × 100 and an r of 2.25 will give a score of b. The final value will never be lower than b, even if r is 2.25 and a Battle Item is used.
The minimum amount that can be rewarded is 100 SP. Master Spirits have an upper limit of 1250 SP, preventing large amounts of SP being gained due to the steep curve.