Montevideo - Uruguay's shock win over Fiji at the Rugby World Cup triggered unprecedented reactions back home in a country where football is king and the majority of its rugby players are non-professionals.

The South American minnows pulled off the greatest upset in their history on Wednesday as they stunned Fiji 30-27 in Kamaishi, catapulting rugby to the top of the news in Uruguay.

World champions in football in 1930 and 1950, it was just Uruguay's third Rugby World Cup win in four tournaments, after victories over Spain in 1999 and against Georgia in 2003.

The defeat of Fiji, who were ranked nine places above them, represents a huge feat for a country where barely 10 000 players - in a population of just over three million - are registered, many of whom are students at top private schools.

"The odds were 15 to 1 and they won," a bus driver in Montevideo bellowed after learning of the result, which fell in the middle of the night in Uruguay.

On the radio and in the papers, sports commentators more accustomed to reporting on the national football team, were suddenly passionate about the oval ball.

"Historic. Los Teros shocked the world of rugby and beat Fiji," read the headline of the digital version of El Pais.

"We are all involved in this story. Those who have followed Los Teros for a while and those who don't know much about rugby but who, in front a 'Celeste' (light blue) shirt on the screen, don't waver," Ignacio Chans, author of a book on the national team, wrote in El Observador.

For Los Teros, a nickname derived from the national bird of Uruguay, the initial goal was to leave Japan with at least one win.

Now, the aim is to register another victory against Georgia, a team in theory closer to their level.

That would enable them to finish third in Pool C, behind front-runners Wales and Australia, and qualify for the next edition in 2023.

"We are not the biggest, we are not the tallest but we came here to win," said Uruguay captain Juan Gaminara, who broke down in tears at the end of the Fiji game.

"We had been preparing for the game for four years. We're a team and we win as a team," added Uruguay's Argentine-born coach Esteban Meneses.