Even allowing for the fact that a replay often takes on a very different texture to the drawn game, the lessons from the first encounter always need to be heeded.
Mayo certainly know that from their rematch with Kerry in last year's semi-final replay, which will have been helpful to them in their planning sessions this week.
Here are five areas where they need to build on the experience from last Sunday's drawn game . . .
He's big, bold and brave but there's a limit to what Aidan O'Shea can do on his own. There were times last Sunday - especially in the first half - when he was isolated deep in enemy territory, with attack dogs everywhere. Meanwhile, his attacking colleagues were scampering from afar, presumably having carried out their instructions to man various checkpoints as part of the plan to disrupt Dublin.
Mayo need to have at least one forward - preferably a proven finisher like Cillian O'Connor - close to O'Shea so that when he wins possession, the Dublin defence have more to concern themselves with than double- or treble-marking him.
Mayo had only 11 points on the board after an hour, a strike rate which loses a whole lot more games than it wins.
They added 1-4 from there on - a strike rate that definitely wins more games than it loses.
Clearly, the balance has to be better if Mayo are to give themselves the best possible chance of winning. Maybe it was the slow start (they trailed by five points after 14 minutes) that drove Mayo into their shells, but there were times when they looked flat-out just coping with the basics.
Mayo are better than that. They scored an average of 2-14 (excluding extra-time) in two games against Kerry last August so the creativity is there. They need to release it more evenly than they did last Sunday.
The Dublin captain was a long way short of his best last Sunday so there must be question marks against his confidence after several seasons when he was lauded as one of the best goalkeepers of all time. It was an exaggeration but then what's new about that in Planet Punditry these days?
Cluxton appears to become frustrated when his kick-out strategies are disrupted, which spreads to other parts of his game too, so Mayo need to make life as awkward as possible for him. Once they adopted that policy last Sunday, it yielded a healthy profit.
The general view is that having recovered so spectacularly last Sunday, the psychological edge rests with Mayo. How reliable is that? Frankly, it's not to be trusted.
Dublin led by 1-3 to 0-1 after 14 minutes and, with a little more precision in attack, could have been even further ahead. It left Mayo needing to use a huge amount of energy to battle back. They know Dublin will try for another quick start on Saturday so Mayo need to be just as smart off the blocks.
Keegan scored the game's first point after 55 seconds last Sunday but wasn't anything like the attacking force he can be from there on, presumably feeling the need to concentrate on defence.
He's brilliant at timing his forward runs - it should be exploited.