Brazil topped the Fifa site audience with seven percent of the total audience. Brazil also had the most engaged audience with 27:46 average monthly minutes/seconds per visitor.
The UK came in second with 6.9% of the audience, according to the measurement and data company.
Alex Burmaster, vice president of global communications for Nilesen's online division, said: "The reach that the Fifa site achieved is impressive considering the kaleidoscopic variety of competing soccer, general sports and news sites available to consumers to follow such a large global event.
"The fact that one in 14 Brazilians online, for example, went to Fifa's site in such a cluttered online environment illustrates a level of achievement."
The US (2.8%) and Japan (0.1%) had the smallest audience on the site. The US audience, however, came in second for most engaged audience with a monthly average of 21:41 per visitor. The Japanese were least engaged with an average monthly visit time of 2:46.
Burmaster said: "The US outperformed expectations in the World Cup and the Fifa site had a highly engaged core of US consumers who averaged more time on the site than fans in more traditionally soccer-mad nations such as England, Germany, Spain and France."
In all countries, the majority of visitors to the site were 18- to 49-years-old.