The high-flying Fijians brushed aside Japan 35-12 in Tokyo at the weekend for a third straight Test victory, after seeing off Tonga and Samoa in previous weeks.
The run has seen them move back into World Rugby’s top 10 rankings for the first time since 2019.
But they face stiffer tests on August 19 against France, the World Cup hosts, in Nantes and seven days later against England at Twickenham.
Fiji will begin their World Cup campaign against Wales in Bordeaux on September 10 before also facing Australia, Georgia and Portugal in Pool C.
“We’ve had an amazing build-up,” Raiwalui said.
“We got to try different combinations against Tonga, Samoa and Japan and were able to come away with victories.
“We have been good in patches and played well. Our fitness has come a long way, but we still haven’t put a game together for the full 80 minutes.
“Now we have huge challenges against France and England. We’ve taken it one challenge at a time, so next up is a very, very good French team.”
Raiwalui has opted for Fijian Drua duo Teti Tela and Caleb Muntz as his first choice fly-halves after leaving out veteran Ben Volavola.
More than half of the squad played for the Drua in this year’s Super Rugby Pacific tournament.
Raiwalui said the experience of playing against top teams from New Zealand and Australia helped raise standards.
“The Drua boys being able to play Super Rugby has been a great opportunity for us and Fiji Rugby,” he added.
“It shows it’s working. We are in the second year of the Drua and I think we’re going to get better”.
Fiji squad for the Rugby World Cup from September 8-October 28:
Props: Eroni Mawi (Saracens/ENG), Peni Ravai (Queensland Reds/AUS), Jone Koroiduadua (Fijian Drua), Mesake Doge (Dragons/WAL), Luke Tagi (Provence Rugby/FRA), Samu Tawake (Fijian Drua)
Hookers: Tevita Ikanivere (Fijian Drua), Sam Matavesi (Northampton Saints/ENG), Zuriel Togiatama (Fijian Drua)
Locks: Isoa Nasilasila (Fijian Drua), Temo Mayanavanua (Lyon/FRA), Te Ahiwaru Cirikidaveta (Fijian Drua), Albert Tuisue (Gloucester/ENG), Lekima Tagitagivalu (Pau/FRA)
Back row: Levani Botia (Stade Rochelais/FRA), Vilive Miramira (Fijian Drua), Meli Derenalagi (Fijian Drua), Viliame Mata (Edinburgh Rugby/SCO)
Scrum-halves: Frank Lomani (Fijian Drua), Simione Kuruvoli (Fijian Drua), Peni Matawalu (Fijian Drua)
Fly-halves: Caleb Muntz (Fijian Drua), Teti Tela (Fijian Drua)
Centres: Josua Tuisova (Racing 92/FRA), Semi Radradra (Bristol Bears/ENG), Waisea Nayacalevu (Toulon/FRA, captain), Kalaveti Ravouvou (Fijian Drua), Sireli Maqala (Bayonne/FRA), Iosefo Masi (Fijian Drua)
Wings: Vinaya Habosi (Fijian Drua), Jiuta Wainiqolo (Toulon/FRA)
Full-back: Ilaisa Droasese (Fijian Drua), Selestino Ravutaumada (Fijian Drua)