It also completes a remarkable story for the 28-year-old, who only took up boxing seven years ago and was working as a pharmacist as recently as last year.
But she has been trained into a world-class boxer by former world champion Anthony Crolla, who saw his charge claim her title at the same arena where he won his own lightweight title, eight and a half years ago.
And Dixon was good value for the unanimous verdict, earning her the WBO belt vacated by Taylor.
Carabajal, 33, meanwhile suffered only the second defeat of her 24-fight career, having previously been beaten by Taylor at Wembley Arena.
Dixon was the more energetic fighter from the off, and scored the critical breakthrough in the early stages of round three as her powerful left found its mark on the South American champion.
It looked as if it would only be a matter of time before Dixon would be crowned champion – but Carabajal showed admirable guts and worried Dixon with some solid punches as the fight wore on, even as the Englishwoman scored with regular body shots.
At the end of round seven, Crolla had to reassure his exhausted fighter: “You’re six minutes away from winning a world title. Do not throw this away. She is every bit as tired as you.”
Carabajal raised a swelling on her opponent’s eye and the final round descended into a slugfest as Dixon’s defences dropped – but she did enough to write another chapter in her remarkable story.
It was a great night for the Crolla family all round, as Anthony’s younger brother William impressively stopped Fabio Cascone in the first round of their light-middleweight bout.
Crolla brought the Italian to his knees just 71 seconds into the second fight of the night with a fierce body shot, to take his own perfect professional record to five wins, four by knockout.