Paris - Republic of Ireland must somehow silence superstar Zlatan Ibrahimovic when they open their Euro 2016 campaign against Sweden at the Stade de France on Monday.
In a Group E also containing Italy and much-fancied Belgium, a defeat for either side could be a decisive blow to their prospects of reaching the last 16.
At 34, Manchester United target Ibrahimovic is probably gracing a major international tournament for the last time after scoring 11 times during qualifying for Erik Hamren's men.
"He's a good player but you can't single him out because they have others who can score goals, as they proved against Wales when there were three goal-scorers and he wasn't one of them," reasoned Ireland's veteran goalkeeper Shay Given, who is back-up to first choice Darren Randolph.
"Still he's a fantastic player, one of the best centre-forwards in the world, but we've got to keep him quiet and the rest of them quiet as well."
Ibrahimovic is familiar with the Stade de France, where he made the last appearance of a prolific four-year spell with Paris Saint-Germain in the French Cup final against Marseille three weeks ago.
Having left Paris, a move to Old Trafford appears to be on the cards and speculation surrounding his future has partly overshadowed Sweden's build-up to the tournament.
Coach Erik Hamren confirmed on Friday that Ibrahimovic would not be allowed to leave the squad's base in Pornichet, on France's Atlantic coast, to finalise his next move.
"It would not be ok for Zlatan to fly to Manchester," Hamren said as he insisted that the rest of his squad are not affected by the constant talk about Ibrahimovic.
"The players of the national team are accustomed to all the rumours surrounding Zlatan too. They are familiar with it. There is absolutely nothing that has affected us negatively in the group."
Veteran goalkeeper Andreas Isaksson, who came off in last weekend's 3-0 friendly win at home to Wales, is expected to be fit for Sweden.
For Ireland the only nagging doubt is a key one, as influential Stoke City forward Jon Walters has been struggling to fully shake off an achilles problem.
In contrast, LA Galaxy striker Robbie Keane (calf) and Everton midfielder James McCarthy (groin and hamstring) should be fine having overcome their injury struggles.
Ireland's last friendly ahead of the tournament saw them lose 2-1 at home to Belarus while Sweden have lost just once in 10 outings but O'Neill did not accept that Ibrahimovic and co are the favourites.
"I don't think that you can judge the favouritism by the the build-up matches, I don't think that at all," O'Neill said at Ireland's base in Versailles, near Paris.
"What you have to do is judge them on records, and Sweden's record in competitions is excellent.
"Qualification they just seem to get through because they know how to do it, and they've got a number of very, very fine players, obviously including Ibrahimovic.
"We've got some very fine players ourselves so we are ready for the game."