Ireland coach Phil Simmons insists no side in the world would dare take liberties with his giantkillers.
With Ashes celebrations still in bloodstreams, England switch to limited-overs mode tomorrow at Stormont and have sent a full-strength side no doubt wary of a shock in the one-day international.
They have already displayed their own vulnerability this summer by succumbing to the might of Holland in the World Twenty20 while Ireland reached the second stage of that competition by defeating Bangladesh, one of the two sides, along with Pakistan, they beat in their joyous 2007 World Cup campaign.
Simmons said: 'I am sure all the full member countries know now, don't underestimate us when you come to play us.
'Come and play properly otherwise anything could happen - no-one is going to take us for granted any more.'
Ireland lost by 38 runs the last time the two countries met in Belfast three years ago and caused a flutter or two in the 48-run defeat in Guyana during that World Cup.
They are a better outfit now, however, after working at improving the start and finish of both their batting and bowling innings.
Captain William Porterfield is one of the men in green with English county experience and played for Gloucestershire as recently as last night - he top-scored with 47 in a Pro40 defeat to Hampshire.
Porterfield, who was 12th man the last time England were in town, said: 'Any chance to play England is a good occasion, and we are looking forward to it. They are obviously on a high after the Ashes.
'I wouldn't say it is quite a David v Goliath but we are obviously underdogs preparing for this game.
'The strides we have made over the last few years has shown we are closing that gap between ourselves and the Test nations, especially in the one-day format.'
Warwickshire fast bowler Boyd Rankin was today ruled out with a groin injury after failing to pass a fitness test.
But former captain Trent Johnston is hoping for a double celebration.
This match represents the Australia-raised all-rounder's 100th appearance for his adopted nation and he said: 'I can hardly say I enjoyed watching England regain the Ashes but on Thursday I have got the chance to get my own back.'
Trinidadian Simmons, meanwhile, revealed he was happy in his role with Ireland despite the West Indies coaching seat remaining vacant following John Dyson's dismissal.
Collingwood demands full focus
Stand-in England captain Paul Collingwood has demanded full focus from his side in Belfast.
Any lingering effects of the Ashes hangovers should have worn off by 11am tomorrow at Stormont, where England begin a month of limited-overs action which also includes two Twenty20 matches and seven one-day internationals against Australia.
Luckily for an England squad including six of the men who clinched a 2-1 series win over Australia, the decisive Oval success did not stretch into Monday.
'Obviously it's a quick turnaround and the schedule isn't ideal,' admitted Collingwood. 'In many ways it was nice to win in four days. It would have been very tough if it had gone into a fifth day.
'But tomorrow is a one-day international against a very good side, as we have seen in the past.
'We have got to get ourselves up for it, simple as that, and put a good performance in.'
England toyed with the idea of sending a shadow side for the 50-over contest before opting to select the same party which will compete against Australia for the NatWest Series, minus Ashes man-of-the-series Andrew Strauss.
'Strauss with the workload he has had as captain deserves a good break, mentally, more than anything else,' said Collingwood.
Teams for tomorrow's RSA international match between Ireland and England at Stormont:
Ireland (from): W Porterfield (captain), A Botha, P Stirling, N O'Brien (wkt), K O'Brien, G Wilson, J Mooney, A White, D Johnston, R West, A Cusack, W McCallan.
England (from): P Collingwood (captain), R Bopara, J Denly, M Prior (wkt), I Trott, E Morgan, O Shah, L Wright, S Broad, A Rashid, T Bresnan, G Swann, R Sidebottom, J Anderson.
Umpires: Asad Rauf (Pak) & P Baldwin.
Match referee: RS Madugalle (SL).
