When a game is finely balanced, as today's Carnegie Challenge Cup so obviously is, a manager's most crucial work is done long before any of the hectic, breathless action begins.
Aside from the usual preparation, tactics, game-plan and mental strategy, he must complete one vital task which is as significant as anything else – naming the squad in which he will place his trust.
Leeds and Warrington are laden with star performers, big-name players and less-heralded individuals who are equally as cherished because of the essential role they play in the team goal.
It is not always an easy task selecting 17, especially for a Wembley final when, unsurprisingly, everyone seems to be fit.
Critics presumed much of today's ensuing battle would be contested around the match-ups at hooker where Leeds duo Danny Buderus and Matt Diskin would be pitched against last year's Lance Todd Trophy winner Michael Monaghan and either Jon Clarke or fellow international Mickey Higham.
However, Wolves chief Tony Smith named his 17 yesterday and growing rumours circling around the Cheshire town proved true: he had omitted exciting young England scrum-half Richie Myler – a 200,000 buy last year – from his match-day plans, meaning Monaghan will start at scrum-half, negating his more potent threat at nine.
It is a gamble for Smith who, while gaining greater experience and doggedness around the ruck, will miss out on Myler's pace and finishing ability.
Smith's opposite number at Leeds, Brian McClennan, is keeping his cards close to his chest – Scott Donald and Chris Clarkson may suffer the axe – but he has his own selection issues to contend with, principally how to deal with the loss of injured prop Jamie Peacock.
The totemic England prop is virtually irreplaceable and it will probably take two makeshift front-rows – Ian Kirke and Greg Eastwood – to begin filling the gap.
Warrington will view Peacock's absence as the chink in Leeds' armour. With the likes of an ageless Adrian Morley, Garreth Carvell and the formidable Ben Westwood, the Normanton-raised back-row in the form of his life, they have the forward vigour to get a hold off Leeds up front, even counting for the return of Carl Ablett.
Both sides have so much firepower at their disposal; it is why so many people are enthralled by this sell-out contest. Keith Senior, the only Leeds player to have won at Wembley, is as explosive as ever at centre and with wing partner Ryan Hall will make the most of any opportunities but Warrington have the prolific Chris Riley and Chris Hicks outside Kangaroo Matt King and a robust Ryan Atkins.
How Smith must also have been tempted to recall England centre Chris Bridge after his successful return from injury in the Carnegie Nines this week. He has ignored that urge, believing his current crop are capable of breaking down the meanest defences.
It is at half-back where the real skirmishes could dictate. Leeds' Danny McGuire, left, is in devastating form and alongside Rob Burrow their added pace and trickery could upset Wolves.
That could be key late on but only if the patched-up Rhinos forwards – also missing Luke Burgess – have subdued their rivals.
The creative talents and kicking game of Lee Briers will also be countered by Leeds Rhinos captain Kevin Sinfield in a fascinating contest.
But the people who will be sweating just as much as the players are the coaches. They will hope they have created the perfect blend and not left the missing vital ingredient on the sidelines.