Wiley's 'Heatwave' is on course to give the rapper his first solo number one single, following his number two hit 'Wearing My Rolex' in 2008.
Meanwhile, Calvin Harris and Example's 'We'll Be Coming Back' is the second highest new entry at number two - just 2,500 copies behind Wiley - and Florence + the Machine's 'Spectrum' completes the top three.
Elsewhere in the top ten, Karmin climb from six to five with 'Brokenhearted', Underworld's Olympics track 'Caliban's Dream' lands at seven, and Rudimental's 'Feel The Love' slips from seven to complete the top ten.
Other new entries as a result of the Olympics Opening Ceremony include Arctic Monkeys' 'Come Together' at 19, and Emeli Sandé's 'Abide With Me' at 32.
On the album chart, Conor Maynard leads the tally with his debut effort Contrast, pushing Plan B's iLL Manors to two.
The Official Chart is announced every Sunday between 4pm and 7pm.
Watch the music video for Wiley's 'Heatwave' below: