Ireland have called Ulster's Jordi Murphy into their World Cup squad after confirming Jack Conan will miss the rest of the tournament with a broken foot.
Leinster star Conan suffered his foot injury in training on Thursday, and had to withdraw from the starting line-up to face Japan in Shizuoka on Saturday.
Ireland suffered one of the great World Cup upsets when losing out 19-12 to the Brave Blossoms, to blow Pool A wide open.
And now Joe Schmidt's men have lost Conan, with Ulster star Murphy drafted in and jetting straight out to Japan as a replacement.
"Jack Conan has been ruled out of the remainder of Rugby World Cup 2019 with a foot injury," read the Irish Rugby Football Union (IRFU) statement.
"He will be replaced in the Ireland squad by Jordi Murphy.
"Jordi will arrive in Japan on Sunday, and will join the Ireland squad in Kobe as they prepare for Thursday's Pool A game against Russia."
Peter O'Mahony had been pressed into service to replace Conan to face World Cup hosts Japan, who overpowered Ireland to register a victory every inch as supreme as their 34-32 win over South Africa at the World Cup in 2015.
Ireland will roll on to face Russia in Kobe on Thursday in what ought to be a walkover, but head coach Schmidt's men will be left to lick their wounds from their shock loss to Japan.
Full-back Rob Kearney will be a doubt to face the Russians after failing a Head Injury Assessment (HIA) during the defeat by Japan.
"Unfortunately Jack Conan has a fracture in his foot, and he will return home to Ireland," said Schmidt, straight after Saturday's match.
"Rob Kearney has got a decent shiner, but he's feeling okay now.
"He failed his HIA as far as I know. If he doesn't pass HIA two and three he will be a confirmed concussion and he would miss the Russia match."
Frustrated boss Schmidt admitted Ireland are now left to play catch-up in the race to qualify for the quarter-finals, with the top two in Pool A heading into the last eight.
Ireland had battered sorry Scotland 27-3 to open their Japan adventure in style, but Saturday's loss to the hosts has halted that momentum.
"Potentially the losing bonus-point could be really important, it means we have six points from two pool games so far," said Schmidt.
"Japan have nine points, and then Samoa have five.
"Keeping that bonus-point allowed us to stay in front of Samoa in the short term.
"Those tight turnarounds are pretty tough going.
"We will I suppose have to chase a little bit now because we want to stay in with a chance of topping the pool. Certainly we've got to get in the top two."