Ireland put their faith in Johnny Sexton

Johnny Sexton during training yesterday. Picture: AP

Ireland have opted to gamble on throwing in their linchpin player from the start against the Pumas in Cardiff tomorrow, even though the Leinster pivot has fought a fitness battle all week.

Sexton trudged out of Ireland’s 24-9 victory over France at the Millennium Stadium after just 25 minutes last weekend, then immediately set about working to be ready for the last-eight encounter.

While Ireland have named their premier playmaker in their starting line-up, the 30-year-old will still most likely use all the available time to ensure his groin issue has healed completely.

When asked if selecting Sexton carried any risk, Ireland head coach Schmidt insisted: “Not really. If he’s fit, he’s fit. We don’t tend to take too many risks with injured players. But there are always risks in everything you do.

“We’ve allowed Johnny to build his way back into the week. He had a fairly light start to the week but trained fully in the Millennium Stadium this morning.

“And we feel he’s ready to go. It’s been a very light training week, we’ve got a few guys carrying bumps and bruises. But we’ve got 48 hours more to freshen and be ready to go on Sunday.”

Ireland must face Argentina without pack leaders Paul O’Connell, Peter O’Mahony and Sean O’Brien, and drafted Jordi Murphy into their back row.

Chris Henry starts at openside flanker as expected, with Iain Henderson therefore slotting in alongside Devin Toner at lock.

Ireland boss Schmidt has resisted the temptation to shift Henderson to blindside flanker and pair Donnacha Ryan with Toner, keeping the changes to a minimum after captain O’Connell’s tournament and Test career-ending hamstring injury. He headed to London for surgery on his torn hamstring on Thursday, but was expected to return to Ireland’s World Cup camp and be on hand for the build-up to the last-eight battle.