Round 26 has eight matches and only one that genuinely decides anything. On Saturday evening in Sydney, the Roosters host the Dolphins in a fixture that will settle the shape of the top four, reroute the minor premiership race, and possibly end a four-season wait that has defined an entire franchise.

Start with the Dolphins, because their stake is the larger one. Kristian Woolf’s side sits fourth on 36 points after a 34-16 dismantling of Parramatta at Suncorp Stadium, their eighth consecutive win at the venue, in front of nearly 25,000. Beat the Roosters and the top four is theirs, a maiden finals appearance, arrived at with a double chance, by a club that has spent three previous seasons fading out of contention in exactly this stretch of the calendar. Lose, and Cronulla sit waiting on 34 with games against Parramatta and Melbourne to come, and the Dolphins’ final round against a Gold Coast side with nothing to lose becomes an ambush waiting to happen.

The Roosters’ predicament is different but no less acute. Trent Robinson’s team went into Sunday afternoon expected to move clear at the top and instead lost 25-24 to a Wests Tigers side on an eight-game losing run, riding a Jock Madden field goal in the 79th minute. That result leaves them third on 38 points, level with the Warriors and Penrith but stranded behind both on differential, plus 162 against plus 295 and plus 294. Three teams, identical points, and the Roosters holding by far the weakest tiebreaker. They cannot win the minor premiership without help, and after Sunday they cannot assume anything about the top four either.

The matchup itself is compelling on its own terms. The Dolphins have led after twenty minutes just five times all season and trailed Parramatta 10-0 before finding themselves, a habit that has worked against ordinary opposition and will not survive a Roosters side that scores early and often.

Herbie Farnworth has been the competition’s most destructive centre for two months, Isaiya Katoa’s balance of kicking and running has grown up considerably in his fourth season, and Jamayne Isaako’s goal-kicking has quietly won them close games all year. The Roosters, for their part, have been without James Tedesco for three straight weeks and lost Victor Radley to a head injury assessment on Sunday, having also had him placed on report.

Both sides carry judiciary risk into the week. Thomas Flegler and Jack Bostock were placed on report for the Dolphins against the Eels, Flegler for a hip drop late in the game, and a suspension there would strip Woolf of pack ballast at the worst possible moment.

The premiership context is not decoration. No side in the game’s history has won it from outside the top four, which means for the loser of this match a season’s work reduces to a knockout week one and a road that nobody has ever completed. That is what makes it the game of the round. Everything else is arithmetic.