Jorja Miller has been ruled out of New Zealand’s Women’s Rugby World Cup semi-final against Canada in a major blow to the Black Ferns’ hopes of defending their title.

The 21-year-old back-row has been one of the outstanding players of the tournament, scoring four tries and impressing in defence.

New Zealand, the record six-time women’s world champions, have yet to confirm the precise nature of Miller’s injury. She featured heavy strapping on her left knee in the semifinal win in which she left the field in the 46th minute.

Saturday’s semifinal against Canada in Bristol will be followed by a third-place play-off and the final, both taking place at Twickenham on September 27.

New Zealand co-captain Kennedy Tukuafu has taken Miller’s place at openside flanker.

Tukuafu’s inclusion is one of four changes to the starting XV following New Zealand’s 46-17 quarter-final win over South Africa, with Sylvia Brunt back in midfield, Risaleaana Pouri-Lane starting at scrum-half and Tanya Kalounivale at tighthead prop.

Co-captain Ruahei Demant retains her first five-eighth role and will win her 50th cap against Canada in Bristol.

New Zealand coach Allan Bunting said his team would benefit from their experience on the big stage.

“We are looking forward to this weekend and the challenge ahead,” he said. “We are a different team, our game is in a different place and we have experience in pinnacle events under pressure.”

Canada, ranked one place above New Zealand at number two in the world, are unbeaten in their past two meetings against the Black Ferns and are expected to give the title-holders their first real test of the tournament in England.

The 2014 runners-up have retained the same matchday 23 that hammered Australia 46-5 in the last eight.

“We have shown over the past two years that we are one of the best teams in the world, and our last two results against New Zealand (a win and a draw) support that,” said Canada coach Kevin Rouet.

“We have every reason to believe that we can win this game. On Friday, we take another step toward the ultimate goal we have been building towards over our first four games and the last three years.”

The other semi-final, on Saturday, pits tournament hosts and favourites England against France, in a match also being staged at Bristol’s Ashton Gate.

Black Ferns: 1. Chryss Viliko, 2. Georgia Ponsonby, 3. Tanya Kalounivale, 4. Maiakawanakaulani Roos, 5. Alana Bremner, 6. Liana Mikaele-Tu’u, 7. Kennedy Tukuafu, 8. Kaipo Olsen-Baker, 9. Risaleaana Pouri-Lane, 10. Ruahei Demant (cc), 11. Portia Woodman-Wickliffe, 12. Logo-I-Pulotu Lemapu-Atai’i Sylvia Brun, 13. Stacey Waaka, 14. Braxton Sorensen-McGee, 15. Renee Holmes.

Bench: 16. Atlanta Lolohea, 17. Kate Henwood, 18. Amy Rule, 19. Chelsea Bremner, 20. Layla Sae, 21. Maia Joseph, 22. Theresa Setefano, 23. Ayesha Leti-I’iga.

Canada: 1. McKinley Hunt, 2. Emily Tuttosi, 3. DaLeaka Menin, 4. Sophie de Goede, 5. Courtney O’Donnell, 6. Caroline Crossley, 7. Karen Paquin, 8. Fabiola Forteza, 9. Justine Pelletier, 10. Taylor Perry, 11. Asia Hogan-Rochester, 12. Alexandra Tessier (capt), 13. Florence Symonds, 14.Alysha Corrigan, 15. Julia Schell

Bench: 16. Gillian Boag, 17. Brittany Kassil, 18. Olivia DeMerchant, 19. Tyson Beukeboom, 20. Laetitia Royer, 21. Gabrielle Senft, 22. Olivia Apps, 23. Shoshanah Seumanutafa.

Coach: Kevin Rouet (FRA) a