Vereniki Goneva scored four tries as Fiji began their World Cup campaign with victory over Namibia in Rotorua.
The rank outsiders led 9-7 when fly-half Theuns Kotze slotted three successive drop-goals before Fiji hit back with tries from Leone Nakarawa and Goneva inside two minutes.
Goneva became the first Fijian to score a World Cup hat-trick when he went over just before the break.
He grabbed another before Naipolioni Nalaga sealed victory late on.
Goneva is the 11th player to score four tries in a World Cup match, with former All Black Marc Ellis the record-holder with six, while two players - Australia's Chris Latham and England's Josh Lewsey - have scored five.
Tries from lock Heinze Koll and full-back Chrysander Botha had given Fiji a fright earlier in the second half but 19 points from the boot of Seremaia Bai ensured that Namibia were always kept at arm's length.
Kotze became only the fourth player to score a hat-trick of drop-goals in World Cup match, after Springbok Jannie de Beer, who landed five against England in the 1999 quarter-finals, England's Jonny Wilkinson and Argentine Juan Martin Hernandez.
"The boys have been eager to get this game over and done with and now all the cobwebs and emotions are out of the way we are looking forward to next week [against South Africa]," said Fiji coach Sam Domoni.
Namibia coach Johan Diergaardt rued his side's leaky defence.
"We made some silly mistakes in the first half and let some easy tries in but I am very proud of the way the guys came back and it is typical of our character," he said.
"I think if our defence was a little bit sharper we would have been in with a chance."
Fiji: Murimurivalu, Goneva, Lovobalavu, Bai, Nalaga, Luveniyali, Kental, Ma'afu, Veikoso, Manu, Nakarawa, Lewaravu, Waqaniburotu, Ravulo, Talei.
Replacements: Keresoni for Murimurivalu (54), Vulivuli for Lovobalavu (67), Buatava for Kental (58), Daveta for Ma'afu (64), Koto Koto for Veikoso (50), Kalou for Lewaravu (74), Qera for Talei (55).
Namibia: Botha, Dames, D. van Wyk, van Zyl, Marais, Kotze, Jantjies, Redelinghuys, Horn, Larson, Koll, Esterhuyse, Du Plessis, Burger, Nieuwenhuis.
Replacements: D. de la Harpe for Marais (69), Winkler for Kotze (78), R. de la Harpe for Jantjies (69), O'Callerghan for Horn (53), van Lill for Esterhuyse (53), Kitshoff for Du Plessis (47).