Distraught Johnny Sexton broke down on realising his groin problem would rule him out of today’s quarter-final clash with Argentina. Ireland ruled Sexton out of their last-eight Pumas battle yesterday morning, after the fly-half pulled up after training on Friday night.

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The 30-year-old fought tooth and nail to be ready for Ireland’s sixth World Cup quarter-final, but lost that battle despite head coach Joe Schmidt declaring the Leinster star 100 per cent fit on Thursday.

Ian Madigan will now start, thrust into the biggest game of his life – with Ireland captain Jamie Heaslip backing the 26-year-old to excel amid the maelstrom.

“Johnny’s a massive loss to us, of course,” said Heaslip. “I know Johnny’s gutted but he’s also helping Ian prepare and doing everything for that. But it doesn’t change the gameplan at all with Ian in there. You saw last week when Johnny came off Ian stepped in and we all get the same gameplan we run through the week.

“He stepped right in and did a great job. Ian’s taken his opportunity every time he’s been called up, and he will do that again.

“We never talk about individuals as such, but we talk about the strength individuals can bring to the group. Granted Johnny is probably one of the best out-halves out there, but playing with Ian for the last couple of years he’s no slouch either. Everyone’s stepping in and taking their opportunity.”

Ulster’s Paddy Jackson takes a seat on the bench as Ireland chase their first-ever semi-final. Schmidt has also drafted in scrum-half Isaac Boss as their replacement for injured Ulster centre Jared Payne, in a bid to offset Sexton’s absence.

Ireland are holding out hope Sexton could be fit for semi-final weekend, but obviously have not projected their plans too far at this point, mindful that Argentina pose a considerable threat.

Everything they produce, plot and plunder revolves around Sexton, from line-kicking to backline steering, to pinpoint goal-kicking.

Sexton’s absence further dents Ireland’s already-depleted resources, squad captain Paul O’Connell and Peter O’Mahony out of the tournament with injuries and Sean O’Brien banned for punching France’s Pascal Pape last week.

Aside from the injury crisis Ireland are going through, one of the mor intriguing subplots to today’s game is 32-year-old Pumas prop Marcos Ayerza and his Irish roots.

The 32-year-old – one of the few remaining players to have been part of the Pumas side that lit up the 2007 World Cup by reaching the semi-finals – has a love of horse racing, becoming very involved in the family stud farm and even calling one of his horses Welford Road after the home ground of his English club Leicester Tigers.

Ayerza said: “I’m one-sixteenth Irish – my great-great grandfather was David O’Connor, who came from Ireland. Playing against Ireland has great pride for my family. “Our links with Ireland are always very strong. We have similar ways of thinking and doing things.”