The Scottish DJ's collaboration with Florence Welch titled 'Sweet Nothing' debuts at number one on this week's chart in Ireland, while Swedish House Mafia are at two with 'Don't You Worry Child'.
Psy is at three with 'Gangnam Style', Rihanna stays put at four with 'Diamonds' and One Direction are at five with 'Live While We're Young'.
Adele's James Bond theme 'Skyfall' falls from the top spot to eight, while Ellie Goulding's 'Anything Could Happen' is at 17.
Justin Bieber and Nicki Minaj land at 22 with 'Beauty and a Beat', Rebecca Ferguson is at 32 with 'Backtrack' and Labrinth and Emeli Sandé advance 20 places to 36 with 'Beneath Your Beautiful'.
This week's Irish Top 10 is as follows:
1. (-) Calvin Harris ft. Florence Welch: 'Sweet Nothing'
2. (2) Swedish House Mafia: 'Don't You Worry Child'
3. (3) Psy: 'Gangnam Style'
4. (4) Rihanna: 'Diamonds'
5. (6) One Direction: 'Live While We're Young'
6. (5) Lykke Li: 'I Follow Rivers'
7. (7) The Script ft. will.i.am: 'Hall of Fame'
8. (1) Adele: 'Skyfall'
9. (11) Taylor Swift: 'We Are Never Ever Getting Back Together'
10. (9) David Guetta ft. Sia: 'She Wolf (Falling to Pieces)'
Watch the music video for Calvin Harris and Florence Welch's 'Sweet Nothing' below: