The track holds off competition for a second week from Enrique Iglesias's 'Tonight (I'm Lovin' You)', which remains at two, while Alexis Jordan's 'Happiness' completes the top three.
Meanwhile, Britney Spears advances from ten to four with 'Hold It Against Me', and Avril Lavigne's 'What The Hell' debuts at number nine.
Elsewhere, Afrojack and Eva Simons leap from 23 to 17 with 'Take Over Control', while Usher's 'More' enters the tally at 23.
Rihanna's 'S&M' lands at 27, and Christina Aguilera's 'Show Me How You Burlesque' is a new entry at 29.
The top ten singles in full (click where possible for our reviews):
1. (1) Wynter Gordon: 'Dirty Talk'
2. (2) Enrique Iglesias ft. Ludacris & DJ Frank E: 'Tonight (I'm Lovin' You)'
3. (6) Alexis Jordan: 'Happiness'
4. (10) Britney Spears: 'Hold It Against Me'
5. (4) Guy Sebastian ft. Eve: 'Who's That Girl'
6. (3) Bruno Mars: 'Grenade'
7. (5) Chris Brown: 'Yeah 3X'
8. (7) David Guetta ft. Rihanna: 'Who's That Chick?'
9. (*) Avril Lavigne: 'What The Hell'
10. (15) The Lonely Island ft. Akon: 'I Just Had Sex'