The singer's winning track 'Impossible' has become the fastest-selling release of 2012 so far after shifting 255,00 copies during its first 48 hours on sale.
will.i.am and Britney Spears are the second highest new entry at two with 'Scream & Shout', while Bruno Mars is at three with 'Locked Out Of Heaven'.
Gabrielle Aplin slides to four with 'The Power Of Love' and Olly Murs and Flo Rida are down to five with 'Troublemaker'.
Rihanna is at six with 'Diamonds' and eight with her new Mikky Ekko collaboration 'Stay'.
Daley and Jessie J are at 19 with 'Remember Me' and Emeli Sandé vaults up to 24 with 'Clown' following her X Factor guest performance.
Over on the album chart, Bruno Mars is on course to claim his second number one record in the UK.
The singer's latest album Unorthodox Jukebox is currently outselling its nearest competitor, Michael Bublé's Christmas, by 22,000 copies.
Green Day start at 14 with Tré, Kelly Clarkson's Greatest Hits - Chapter One is at 18 and Kylie Minogue's The Abbey Road Sessions is at 25.
Watch James Arthur perform 'Impossible' on the X Factor live final below: