The Pacific Islanders will take on the Welsh in Hamilton on Sunday with both sides aware that a loss is likely to consign them to a flight home before next month's quarter-finals.
Former scrum half Tagitau kicked eight points against Wales in Samoa's stunning 16-13 victory in Cardiff at RWC 1991.
He said Samoan fans were confident their team can create another upset. "It's just been great, the amount of support," Tagitau said. "The country is gearing up for this match. We have a long history against the Welsh so it's exciting and a great build-up."
There is little chance of Wales underestimating Samoa, who also beat them 38-31 in RWC 1999, after the Islanders' shock defeat of Tri Nations champions Australia in July and their 37-point win over Namibia on Wednesday in their RWC 2011 opener.
Fired-up Welsh
Tagitau believes the Welsh will bounce back strongly from their heart-breaking defeat to RWC champions South Africa.
"Judging by what (Wales coach) Warren Gatland has said in the media, I think they'll be very motivated," he said.
"They'll be disappointed with that loss so we're expecting a fired-up Welsh side."
Wales will have enjoyed a seven-day turnaround from the Springboks defeat, compared with four days for the Samoans who are reeling from injuries to mercurial fly half Tusi Pisi (hamstring) and flanker Taiasina Tuifua (ribs).
Pisi, who looked sharp against Namibia before being forced from the field in the first half, is the bigger selection concern while Tuifua has a strong chance of playing against the Welsh.
Wrecking-ball wing
Samoa's wrecking-ball wing Alesana Tuilagi, who plays for English club Leicester Tigers, will be hoping to add to the three tries he scored against an outclassed Namibia.
Asked whether he found it difficult to maintain his playing weight, the 121kg Tuilagi said at a team recovery session on Thursday: "It's really hard because we love our food back home.
"We love loads of meat. When you go back home from the UK, you tend to eat a lot."
Samoa full back Paul Williams revealed a screening of photos from Samoa fans on Tuesday night had inspired the players to show no mercy against Namibia.
"We had a compilation of photos put together from around the world and we watched that the night before our game," he said. "That was really overwhelming and quite special."
RNS dp/ig/tc
