The singer tops the tally for a fifth consecutive week, holding off Birdy's 'Skinny Love' and Flo Rida's 'I Cry', which remain at spots two and three respectively.
Meanwhile, Taylor Swift moves five to four with 'We Are Never Ever Getting Back Together', Owl City and Carly Rae Jepsen complete the top five with 'Good Time', and Psy's 'Gangnam Style' debuts at number seven.
Outside the top ten, David Guetta and Sia's 'She Wolf (Falling to Pieces)' jumps 16 to 14, Ne-Yo leaps 24 to 17 with 'Let Me Love You', and Rita Ora's 'R.I.P.' bounds 23 to 18.
Alicia Keys debuts at 25 with 'Girl on Fire', Timomatic's 'Incredible' starts at 27, and Sam & the Womp's 'Bom Bom' vaults 46 to 34.
Further down the chart, Of Monsters and Men enter at 42 with 'Little Talks', and Ed Sheeran bows at 50 with 'Lego House'.
1. (1) Guy Sebastian ft. Lupe Fiasco: 'Battle Scars'
2. (2) Birdy: 'Skinny Love'
3. (3) Flo Rida: 'I Cry'
4. (4) Taylor Swift: 'We Are Never Ever Getting Back Together'
5. (6) Owl City ft. Carly Rae Jepsen: 'Good Time'
6. (4) Justice Crew: 'Boom Boom'
7. (*) Psy: 'Gangnam Style'
8. (8) The Script ft. will.i.am: 'Hall of Fame'
9. (7) Maroon 5: 'One More Night'
10. (9) Far*East Movement ft. Cover Drive: 'Turn Up the Love'
Watch the music video for Guy Sebastian's 'Battle Scars' below: