'The Fox' became the second Norwegian song ever to make the list, after it leapt from 13th to 8th place. The feat was last achieved by A-ha's 'Take on Me' back in 1985.
The song has now sold 71,000 digital downloads, up 21 percent on last week, and has been streamed 9.5 million times, a 34 percent increase on last week, making it this week's 'digital gainer' on the index.
The song's YouTube video had been seen 79 million times by Thursday morning.
Bård and Vegard Ylvisåker have had a career in Norway as a comedy and variety act since 2001, but achieved international success only this Septembert with the release of The Fox, which was originally intended as a marketing tool for their talk show.
At the end of last month, they appeared on the Ellen DeGeneres show, one of the US's most-watched afternoon talk shows, and performed at a festival in Las Vegas.