Football21 was a weekly free-to-enter competition, created by William Hill, UNILAD and SportCaller, which allowed players to compete for a £10,000 prize pot every weekend by selecting teams whose combined goal-count adds up to 21.

The rules dictate that each selected side must score at least one goal, but players can choose from as many or as few teams as they wish to produce the 21-goal aggregate total.

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Although available on desktop, this was primarily a mobile focussed product and it showed in the UX, making playing as easy as a few taps.