Tokyo - A fit-again Robbie Henshaw will make his first World Cup appearance in Japan on Saturday after being named to start in Ireland's crucial match against Samoa in Fukuoka.
Ireland need a bonus-point win to ensure they qualify before the final Pool A showdown on Sunday between hosts Japan and Scotland - if Typhoon Hagibis allows it to proceed.
"We can't control what happens with the Japan-Scotland game, so on Saturday it's up to us to get our business done as best we can," coach Joe Schmidt said when naming his side Thursday.
Ireland-Samoa, played in the country's southwest likely to be spared by Hagibis, is the only game on Saturday to go ahead and Pool A is the only pool with qualification still up for grabs.
If Ireland win without a bonus point it will put them at risk of finishing third despite losing only one game as the pool goes down to the wire with Japan on 14, Ireland on 11 and Scotland on 10.
The return of the 38-Test centre Henshaw, who suffered a hamstring injury soon after arriving in Japan, is one of 11 changes from the side that beat Russia 35-0 as Schmidt zeros in on his first-choice line up.
"Robbie is fresh and we're excited to have him in there. It is a little bit about balancing the load as well, albeit in a huge game for us," Schmidt said.
Halfbacks Conor Murray and Johnny Sexton will start together for the 55th time, equalling the Ireland record set by Peter Stringer and Ronan O'Gara between 2000 and 2015.
Sexton, Bundee Aki, Tadhg Beirne and Keith Earls are the only survivors from the Russia match while hooker Rory Best returns to captain Ireland for the 37th time, overtaking Keith Wood and moving into second place behind Brian O'Driscoll (83).
Only flanker Peter O'Mahony and fullback Rob Kearney are missing from what is thought to be Schmidt's preferred starting line-up.
O'Mahony and Garry Ringrose are the only two Ireland players that have started in the first three matches. The former is on the bench against Samoa and the latter has the weekend off.
The cancellation of the Pool B match between New Zealand and Italy means Ireland know that winning the group means a quarter-final against South Africa. Finishing second means they play the All Blacks.
"We've just got to make sure our game gets finished with the right result for us," Schmidt said.
"I only know what we need to do, and we need to get out and get a result. It's a situation nobody wanted to have. I know there are several teams who are massively disappointed their games have already been abandoned."
Samoa, with their quarter-final hopes ending in defeat to Japan last Saturday, have made two changes with prop Logovi'i Mulipola and lock Teofilo Paulo coming into the pack.
15 Jordan Larmour, 14 Keith Earls, 13 Robbie Henshaw, 12 Bundee Aki, 11 Jacob Stockdale, 10 Johnny Sexton, 9 Conor Murray, 8 CJ Stander, 7 Josh Van der Flier, 6 Tadhg Beirne, 5 James Ryan, 4 Iain Henderson, 3 Tadhg Furlong, 2 Rory Best (captain), 1 Cian Healy
Substitutes: 16 Niall Scannell, 17 Dave Kilcoyne, 18 Andrew Porter, 19 Jean Kleyn, 20 Peter O’Mahony, 21 Luke McGrath, 22 Joey Carbery, 22 Andrew Conway
15 Tim Nanai-Williams, 14 Ah See Tuala, 13 Alapati Leiua, 12 Henry Taefu, 11 Ed Fidow, 10 Ulupano Seuteni, 9 Dwayne Polataivao, 8 Jack Lam (captain), 7 TJ Ioane, 6 Chris Vui, 5 Kane Le’aupepe, 4 Teofilo Paulo, 3 Michael Alaalatoa, 2 Seilala Lam, 1 Logovii Mulipola
Substitutes: 16 Ray Niuia, 17 Paul Alo-Emile, 18 Jordan Lay, 19 Piula Faasalele, 20 Josh Tyrell, 21 Pele Cowley, 22 Tusi Pisi, 22 Kieron Fonotia