World Player of the Year Jonathan Sexton will captain Ireland for the first time after being recalled for their Rugby World Cup match against Russia on Thursday following a thigh injury.
The 34-year-old fly-half missed Ireland's shock 19-12 defeat by hosts Japan in Shizuoka on Saturday, which threw Pool A wide open, with a knock he suffered in the opening 27-3 win over Scotland.
British and Irish Lions star Sexton was one of 11 personnel changes made by Joe Schmidt following a five-day turnaround, in what is the New Zealander's last tournament before he steps down as Ireland coach.
He gave Jordi Murphy an immediate start at No 8, with the back-row having only recently arrived in Japan to replace the injured Jack Conan in the 31-man squad.
Meanwhile centre Garry Ringrose and flanker Peter O'Mahony will both be starting their third game in 11 days when Ireland face Russia in what are set to be sweltering conditions under the closed roof of the Kobe Misaki Stadium.
Leinster's Ringrose will partner the returning Bundee Aki in midfield, with Chris Farrell ruled out of the Russia game due to concussion and Robbie Henshaw still to regain full fitness following hamstring trouble.
The Irish will also field an all-Munster front-five against Russia, with Tadhg Beirne and Jean Kleyn in the second row.
Meanwhile versatile Munster fly-half Joey Carbery will cover scrum-half from the bench.
Ireland will now look to beat both Russia and Samoa in their two concluding pool fixtures and may well need bonus points from both games to be certain of gaining one of the two quarter-final spots on offer from a tightly-contested Pool A.
The Irish will have to make history if they are to be crowned world champions for the first time, as every side that has lifted the Webb Ellis Cup has gone through the tournament unbeaten.
Rob Kearney; Andrew Conway, Garry Ringrose, Bundee Aki, Keith Earls; Jonathan Sexton (capt), Luke McGrath; Jordi Murphy, Peter O'Mahony, Rhys Ruddock; Jean Kleyn, Tadhg Beirne; John Ryan, Niall Scannell, Dave Kilcoyne
Replacements: Sean Cronin, Andrew Porter, Tadhg Furlong, Iain Henderson, CJ Stander, Joey Carbery, Jack Carty, Jordan Larmour
Kobe, Japan | AFP