The Scottish band's sixth studio album sold 71,500 copies, which is the biggest opening week sales of an album so far in 2013.
"Opposites feels like the best record we've ever made and to have it sitting atop the Official Albums Chart is a huge honour," the band told The Official Charts Company. "Thank you so much to all our fans."
Their previous albums Puzzle and Only Revolutions reached number two and three respectively, selling 37,000 and 43,000 in their first weeks on sale.
The cast recording of Les Misérables drops one place to two, while Fleetwood Mac's Rumours leaps up to number three, 35 years after its original release.
Emeli Sandé drops two places to four with longrunner Our Version of Events. Justin Bieber's acoustic version of Believe is new at five.
Andrea Bocelli lands at nine with his 14th studio album Passione. Ellie Goulding climbs three places back into the Top 10 with Halcyon at ten.
Alicia Keys leaps 25 places to 13 with Girl on Fire, while Little Mix are up 15 spots to 25 with DNA.
Funeral for a Friend's sixth studio album Conduit is a new entry at 34.
Source: Official Charts Company
> This week's singles chart
View the latest Official Top 100 Album Chart