The Kimbra collaboration, which last week became the first track of 2012 to sell over 500,000, sold only 20,000 copies more than nearest rival Nicki Minaj.
Minaj's 'Starships' climbs another two places to finish runner-up, just ahead of Alexandra Burke whose new entry 'Elephant', featuring Erick Morillo, debuted in third place.
Emeli Sandé's 'Next To Me' and Flo Rida's 'Wild Ones' dropped off to fourth and fifth place.
David Guetta makes two appearances in the Top 10, with 'Titanium' at number six and 'Turn Me On' at number eight, both up two places respectively.
Girl group StooShe fell five spots to nine with their Travie McCoy team-up 'Love Me', while Marcus Collins's 'Seven Nation Army' slipped to 12, falling out of the Top 10 after two weeks.
After a slow start in the midweeks, Swedish House Mafia were this week's second highest-rated new entry, arriving at 13 with 'Greyhound'.
Meanwhile, Jay-Z and Kanye West rose three places to reach number ten with 'Paris'.
Source: Official Charts Company
> This week's album chart