Last Friday proved a momentous day for pop fans: not only was Katy Perry's new album 'Witness' released, but Taylor Swift made the ultimate petty move by deciding to reinstate her back catalogue on Spotify at the exact same time, in what many saw as a bid to overshadow her rival's new release.

Well, it looks like it's worked - as Swift's music has been outperforming Perry's, at least in the US.

As Consequence of Sound point out, Swift had seven songs in the Spotify US Top 200 as of Monday (and two in the Top 100) and more streams overall - but Perry has only four (two of which are in the Top 100).

As of yesterday, however,  the global Top 200 had Perry's 'Swish Swish' ranked higher (#41) than Swift's highest entry ('Shake It Off' at #124), and her three songs were streaming bigger figures than Swift's five entries combined. It'll be interesting to see what story the weekly charts tell on Friday.

In Ireland, meanwhile, yesterday Perry was on 28,522 streams for her three tracks in the Top 200 (Swish Swish, Bon Appetit and Chained to the Rhythm), while Swift was on 21,174 for her eight songs.

Although Perry has said she's '100% ready' to end the feud with Swift, something tells us that we might not have heard the last of this story...