Coach Andy Farrell has made a number of changes to the side that ran in 12 tries in an 82-8 rout of Romania in their opening game, with World Player Of The Year Josh van der Flier and winger Mack Hansen restored to the starting lineup.
Conor Murray comes in for James Gibson-Park at scrumhalf with Ronan Kelleher picked at hooker in place of Rob Herring, while the centre pairing of Bundee Aki and Garry Ringrose is left unchanged.
After a 24-point haul against Romania, Sexton needs 10 more points to overhaul the 1,083 racked up by his predecessor Ronan O'Gara.
With the Tongans set to enter the fray this weekend, the Irish top the pool ahead of South Africa, who beat fourth-placed Scotland 18-3 in their opener. Romania are bottom.
Ireland team (caps in brackets):
15. Hugo Keenan (Leinster) (32)
14. Mack Hansen (Connacht) (17)
13. Garry Ringrose (Leinster) (53)
12. Bundee Aki (Connacht) (48)
11. James Lowe (Leinster) (22)
10. Johnny Sexton (Leinster)(captain) (114)
9. Conor Murray (Munster) (108)
1. Andrew Porter (Leinster) (55)
2. Ronan Kelleher (Leinster) (22)
3. Tadhg Furlong (Leinster) (68)
4. Tadhg Beirne (Munster) (42)
5. James Ryan (Leinster) (56)
6. Peter O'Mahony (Munster) (97)
7. Josh van der Flier (Leinster) (53)
8. Caelan Doris (Leinster) (32)
Replacements:
16. Rob Herring (Ulster) (38)
17. David Kilcoyne (Munster) (52)
18. Finlay Bealham (Connacht) (32)
19. Iain Henderson (Ulster) (75)
20. Ryan Baird (Leinster) (13)
21. Craig Casey (Munster) (12)
22. Ross Byrne (Leinster) (21)
23. Robbie Henshaw (Leinster) (65).
