The 20-year-old, who first reached pole position in 2009 with debut tracks 'Mama Do' and 'Boys And Girls', kept Maroon 5 and 'Moves Like Jagger' in the runner-up spot for a second week.
The Saturdays once again just miss out on their first UK number one with their latest release 'All Fired Up', their tenth Top 10 single since 2008, while Leona Lewis returns to the chart with her Avicii collaboration 'Collide' at four.
Last week's number one 'Stay Awake' by Example concludes the top five and Olly Murs stumbles three to six with 'Heart Skips A Beat'. Ed Sheeran rounds out this Sunday's best sellers with 'You Need Me, I Don't Need You', down six from its previous finish of four.
Snow Patrol, meanwhile, are denied a return to the Top 10 as their new track 'Called Out In The Dark' debuts at 11, settling in next to 'Jealousy' by Will Young, which is down four in its third week of release.
Former chart-topper 'Don't Go' by Wretch 32 crashes six places to 13, while Adele's mega-seller 'Someone Like You' storms ten spots back up the chart to 17.
The 21 musician also appears at 20 with 'Set Fire To The Rain', which is down five from last Sunday, to wrap around 'The A Team' by Ed Sheeran and Emeli Sandé's 'Heaven', which slip five and eight digits respectively to 18 and 19.
The Top 10 in full:
1. (-) Pixie Lott: 'All About Tonight'
2. (2) Maroon 5 ft. Christina Aguilera: 'Moves Like Jagger'
3. (-) The Saturdays: 'All Fired Up'
4. (-) Leona Lewis ft. Avicii: 'Collide'
5. (1) Example: 'Stay Awake'
6. (3) Olly Murs ft. Rizzle Kicks: 'Heart Skips A Beat'
7. (5) Calvin Harris: 'Feel So Close'
8. (6) Christina Perri: 'Jar Of Hearts'
9. (10) Sean Kingston: 'Party All Night (Sleep All Day)'
10. (4) Ed Sheeran: 'You Need Me, I Don't Need You'
Source: Official Charts Company
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