Derry have been the big Ulster under-achievers in the championship. Never mind the fact that they failed to add to the All-Ireland glory of 1993, but they know they've been starved of provincial success for far too long.
They have always been very talented, but they have been missing the grit, determination and steel that needs to be incorporated with that ability. And that is what Damien Cassidy brings to a team - a totally focussed approach, a la what Clonoe experienced. He will have instilled a very focussed approach and the iron resolve will be very evident.
Cassidy, pictured right, made no bones about where he stands when he summarily dismissed criticism of their performance after the Monaghan match by saying he's not out to entertain and the result is all that matters.
What we will see is a completely different Derry team to that which played under Paddy Crozier and even before that. The personnel may be along much the same lines, but the way they play and their blinkered attitude will be different to what went before.
Now they will miss Fergal Doherty, there's no doubt about that. Derry with him in their team is a completely different outfit to Derry without him. Physically very strong and with tremendous vision, he's a key member of the side. Who'll fill the gap? Maybe Patsy Bradley will be fit to do that, but I feel that the jersey will more than likely be entrusted to Enda Muldoon.
Talking of Tyrone, I would not be anywhere near as carried away about the display against Armagh as some appear to be.
The defence played very well for 80 per cent of the game, but were not nearly as influential in the last ten minutes.
To a large degree, the attack was atrocious. They went 20 minutes without scoring and had no focus and were lackadaisical. I'm not naming names, but the half-forward line was particularly guilty. The first half was brutal, that's the only way I can put it - and that will definitely not do against Derry.
Derry's half-backs are very capable and especially influential, most notably Paul Cartin and Barry McGoldrick who is usually good for three or four points as well - with Sean leo McGoldrick not far behind them. Facing men of that calibre, the Tyrone half-forwards need to knuckle down and a good kick up the backside would do them no harm.
Incidentally, I wonder whether there's any truth in the rumours that James Conway might not be in the Derry squad for Casement Park?
Moving on, let me say again that I still believe we do not get nearly enough from Sean Cavanagh. He's a fabulous footballer and we get occasional glimpses of his genius, but Brendan Donaghy showed the last day that he can be almost marked out of a game if the back is willing to sacrifice his own reputation in order to fulfil that negative role. Kevin McCloy is capable of doing that job, but he may be tempted to play football - which is what he does best.
The world and its mother saw that the long ball in gave Tyrone trouble and it paid big dividends for Armagh towards the end. And I suspect Derry may feel it's the right ploy for the Bradleys who'll be waiting for that sort of supply. But, as somebody else observed, Micky Harte saw that as well and may have a counter-plan.
I believe he may opt to pull Joe McMahon deep into a sweeping role to negate that tactic, but then that might give a bit more freedom to the Oak Leaf half-backs and allow them to come up more often to join the attack - and that all adds to the fascination of this fixture.
Leaving Clones after the quarter-final win, I said to myself 'Thank God we have Stevie O'Neill in the team'. And I feel he may be the catalyst to victory on Sunday. And I hope Brian Dooher is fit to join the action at some stage. He looked akin to a cripple as he went on against Armagh but, once he got the ball, what a player he showed himself to be.
In summary, Tyrone are tipped to win, but it's not going to be easy - and maybe far from pretty as well.