The Bajan pop singer previously reached the summit with 'SOS' (2006), 'Umbrella' (2007) and 'Don't Stop The Music' (2007).
Jason Derulo's 'In My Head' slips to two after a fortnight at the top, while David Guetta and Kid Cudi's 'Memories' jumps from six to three.
Meanwhile, Cheryl Cole enters the top ten at number nine with her debut solo single '3 Words'. She has previously notched up three Aussie top 40 hits as a member of Girls Aloud, the most successful of which, 'Jump', peaked at number 23 in 2003.
Outside of the top ten, Timbaland and Katy Perry leap from 26 to 16 with 'If We Ever Meet Again', while Black Eyed Peas debut at 30 with 'Imma Be'.
The top ten singles in full (click where possible for our reviews):
1. (2) Rihanna: 'Rude Boy'
2. (1) Jason Derulo: 'In My Head'
3. (6) David Guetta ft. Kid Cudi: 'Memories'
4. (5) The Midnight Beast: 'Tik Tok'
5. (4) Owl City: 'Fireflies'
6. (3) Iyaz: 'Replay'
7. (16) Train: 'Hey, Soul Sister'
8. (9) Ke$ha ft. 3OH!3: 'Blah Blah Blah'
9. (11) Cheryl Cole: '3 Words'
10. (7) Taylor Swift: 'Today Was A Fairytale'