This is the litmus test for Waterford. A defeat here would not cancel out the worth of their unexpected league triumph or the advances they made in the Munster championship but joining the last four of the All-Ireland championship would add a flourish to a remarkable turnaround in one year.
If there has been any pattern beyond Kilkenny’s enduring quest for excellence in recent years, it has been that other counties have come in a rush, like Clare in 2013 and, to a lesser extent, Wexford a year ago. Waterford’s form has been the chief novelty of this season and they will be keen to extend their run.
The stakes are different now in that they find themselves back in Thurles in a match in which they are widely expected to win.
Ger Cunningham's first season with Dublin has been a bit of a baptism for both manager and team. Anthony Daly was always going to be a tough act to follow, and Dublin's uneven displays in the league were to be expected.
But the nature of the defeat to Galway in the Leinster semi-final replay was chastening and exposed the frailties in a defence sorely lacking the steadying influence of Peter Kelly. His expected return here greatly deepens the cover.
Even so, Dublin's perceived vulnerability through their fullback line presents Derek McGrath with a dilemma. Withdrawing Colin Dunford to act as a general worker and runner and leaving Waterford with Maurice Shanahan as the focal point of the attack has been the basis for Waterford's successful season.
Their crowded, well-organised defence and swift counter-game succeeded even in sucking Tipperary out of their rhythm for periods of the Munster final. But it may be tempting for McGrath to try to apply some pressure on the Dublin backs by opting for a traditional forward line to see if anything gives.
Dublin can point to the fact that after everything they are still here. They hung around against Limerick long enough to punish TJ Ryan’s men for not putting them away when they had the chance.
They have been semi-finalists in 2010, 2011 and 2013: they know their way around days like this. Paul Ryan, David O'Callaghan and Liam Rushe took hold of the game during the critical minutes against Limerick.
Limiting the influence of Austin Gleeson will become a priority for Cunningham, as will finding a path through the immaculate covering defence of Tadhg de Burca: even a goal-getting machine like the Tipp forward line struggled to open up Waterford’s last line.
At the other end, Dublin need to try to limit the ball going through Michael Walsh and Waterford's other senior man Kevin Moran.
Judicious shot selection is critical for Waterford: that more than anything undermined their efforts against Tipperary. If they can add that bit of guile to their repertoire here they can move on to the next tier.
Odds: Dublin 2/1 Draw 9/1 Waterford 8/15.
Last meeting: In 2005, in the All-Ireland qualifiers, with the result Waterford 4-17 Dublin 1-3.
Just the ticket: Stand tickets cost €30 with a €10 rebate for students and OAPs. Killanin and Town End tickets are €20. Juveniles €5.