TODAY'S game against Croatia could be make or break for Ireland's captain and leading scorer, Robbie Keane. Unless he can rediscover the form and clinical finishing which has brought him to this pinnacle, the likelihood is that manager Giovanni Trapattoni will turn to younger, more energetic players to lead the attack.
Coming into camp on the back of disappointing displays in the USA, and with a slight hamstring strain, was not ideal for Keane. Immediately, his future tenancy of both the striker role and the captaincy were under pressure.
Fears in relation to his fitness have been allayed to some extent with hour-long appearances against Bosnia & Herzegovina and Hungary, but his performances have not eliminated the doubt that he is short of form.
Adding to the pressure he is under is the form being shown by the players vying with him for the striking role. Shane Long replaced him against Bosnia & Herzegovina and scored the winner in an eye-catching display, while Jonathan Walters added to his growing reputation when replacing Kevin Doyle in that game and also in last Monday's 0-0 draw with Hungary.
Simon Cox was Keane's replacement against Hungary, and his composure at this level -- three goals in 12 appearances, mainly as sub -- augurs well for his future prospects.
Having such an array of younger talent capable of energising his attack is a welcome change for an Irish manager. In the past, strikers tended to come in single file -- one per generation.
How Trapattoni maximises his striking riches will help determine the success or failure of the Republic of Ireland in Euro 2012. In that respect, he is also under pressure, and can be expected to show his ruthless side if results are not going his way.
Keane will start today, but how long will he remain on the pitch? Are those 60-minute appearances the benchmark for the Group games?
The likelihood is that, if Keane fails to deliver, Trapattoni will show his ruthless side. He has done so with the easy calls so far -- Andy Reid, Kevin Foley -- but dropping or even substituting Keane will be a hard call.
To be fair to Keane, to ask him to play three games in nine days against such high quality opposition is probably too much. At this stage of his career, he is probably better suited to an impact substitute role.
Trapattoni makes great play on loyalty, but as we have seen with Foley, that only goes so far. Ultimately, it is all about the result, and the result is all about putting the best team on the pitch.
He has given Keane the green light to start today's game, but the captain will be conscious that failure to deliver could mean a sideline seat for the remainder of the tournament.
Charlton's team went on to the World Cup quarter-finals, justifying his actions. Faced with the Group of Death, many people feel that a quarter-final spot is beyond Trapattoni's team, but if he plays his cards right he may prove the doubters wrong yet again.
The suggestion that he may need to play a fifth midfielder could be a straw in the wind.
In the past, the manager has depended on Keane and Doyle working hard enough closing down defenders to obviate the need for an extra body in midfield.
If he is having second thoughts at this stage, it could be that he no longer feels Keane or Doyle are up to that demanding role.
Either way, it is all set up for the younger legs to get their chance -- and Keane to announce his retirement when Ireland's course at Euro 2012 is run.