Isaiya Katoa's field goal iced a 25-24 boilover against New Zealand last week that sent Tonga to its first tier-one final, to be played at CommBank Stadium on Sunday.
It also marked Tonga's first defeat of a tier-one nation since their famous 16-12 win over Australia in 2019.
That Auckland game was a watershed moment in international rugby league, a warning shot for Pacific nations announcing themselves as genuine competition for Australia, New Zealand and England.
"That was probably my favourite game of my career thus far," Fonua-Blake said.
"Back then I was a younger guy in the group, it didn't really sink in to me how much it would mean to the fans and the country.Â
"Now that I'm a bit older and we put ourselves back in the position to replicate that, I sort of pinch myself. These moments don't come along that often."
A two-time Dally M Prop of the Year and 182-game NRL veteran, Fonua-Blake said lifting the Pacific Cup on Sunday would top that 2019 win on his list of rugby league achievements.
"Definitely," the Tongan captain said.
"This is probably the biggest game that Tonga has ever played in. All the boys are aware of it and we're just pinching ourselves."
Daniel Tupou, who also played in Tonga's game-changing win over Australia, said only the Sydney Roosters' premiership wins could pip a victory over the Kangaroos on Sunday.
Tupou memorably featured in NSW's 2014 State of Origin series win, which snapped a run of eight consecutive Queensland triumphs, and holds the Roosters club record for most tries.
"I was fortunate to play in grand finals and big games and it would definitely be top of the list, or second to a grand final. It'll be up there," he told AAP.
"Just to be able to accomplish something like that, for our small little country, a country of 100,000 people, which is not much. But it would mean so much to them, to our families, to ourselves."
Born in Sydney to Tongan parents, Fonua-Blake felt victory on Sunday would prove the ultimate vindication for his family's decision to settle in Australia.
"This is more than just a game for me," he said.
"This represents what my family came to Australia for, they came here for a better life and I'm the one reaping the rewards for all their hard work and all their sacrifices.
"I'm just happy that I get to repay them and show them it was the right decision."
Jason Taumalolo, Haumole Olakau'atu and Fonua-Blake have all been longlisted for the International Rugby League's Golden Boot Award in recognition for Tonga's strong campaign.
Fonua-Blake was confident of big celebrations if one of the trio becomes the first Tongan to be crowned the best player in the international game.
"There's a number of boys in this team that could get it," he said.
"They're all freaks. If they did get it, I'm pretty sure Tonga would hold a party or maybe put a statue of them back in Tonga. Fingers crossed."
GOLDEN BOOT NOMINEES:
Herbie Farnworth (England), Addin Fonua-Blake (Tonga), Harry Grant (Australia), Lachlan Lam (Papua New Guinea), Zac Lomax (Australia), Jarome Luai (Samoa), Keano Kini (New Zealand), Nene Macdonald (Papua New Guinea), Esan Marsters (Cook Islands), Taane Milne (Fiji), Haumole Olakau'atu (Tonga), Harry Smith (England), Jason Taumalolo (Tonga), Tom Trbojevic (Australia), Roger Tuivasa-Sheck (Samoa), George Williams (England), Isaah Yeo (Australia)
