The girls beat off competition from fellow X Factor alumni Ella Henderson and her collaboration with Sigma on Glitterball.
The folks in charge of counting those all important sales and streams at at the Offical Charts Company report today:
The lead single from the group’s upcoming third studio album Get Weird, Black Magic this week outsold its nearest competitor - Years & Years’ King (2) - by nearly 7,000 copies.
This week’s highest climber is dance duo Sigma’s Glitterball ft. Ella Henderson. The track, which is also the most downloaded song of the week, first entered the Official Chart at Number 182 on streams alone last week and climbs a mammoth 178 places this week upon its full sales release, to land at 4.
Elsewhere on the charts today and there's another X Factor act in the top 40.
Former JLS star Aston Merrygold has gone solo and makes his Official Chart debut with Get Stupid at Number 28.
Meanwhile today saw One Direction release their newest single Drag Me Down.
The track, out for download now, is the group's first new song since Zayn Malik quit.