The singer’s fans have been downloading the song – which featured in her setlist during her Manchester Arena gig on Monday night – in tribute to the victims of the terror attack.
Now, the emotional dance ballad is sitting at No 1, passing former One Direction singer Liam Payne’s debut single Strip That Down.
The song has also pushed Justin Bieber’s new single with Luis Fonsi and Daddy Yankee, Despactio, back down the list too.
One Last Time is now set to re-enter the Top 40 on this week’s Official Singles Chart, in the wake of the devastating attack in Manchester.
The track climbed from outside the Top 200 overnight to number 35 in today’s Official Charts Company sales flash.
The single is taken from Ariana’s 2014 album My Everything, and originally peaked at Number 24 back in June 2015.
Among the victims of the horrific attack, was YouTube “icon” Martyn Hett.
She wrote to her followers: “Devastated to learn that one of the victims in Manchester was part of the #Lambily [sic].”
Lambily is the term used to describe Mariah’s fanbase.
She added: “RIP Martyn Hett. We will cherish your memory forever.
“His family and all the families affected are in my thoughts and prayers. MC.”