Hennessy arrived at the Copper Box with momentum behind her and, as ever, walked to the ring smiling as she soaked up the occasion.
The Kent fighter has built a strong following, helped by a viral video charting her journey from an overweight youngster to a bantamweight contender on the cusp of world honours.
The quick-footed Hennessy settled into her rhythm, working behind her jab, but Bouttell, 29, was not in London to make up the numbers.
She pressed forward to close the distance, with both fighters cut after the accidental head clash – Hennessy on the forehead, Bouttell under her right eye.
Hennessy landed a sharp combination in the fourth, but Bouttell continued to march forward, landing heavy hooks in the middle rounds.
Promoter and manager Mick Hennessy cheered his daughter on from ringside, while Bouttell’s family, watching her compete in the UK for the first time, made their voices heard.
Bouttell’s punches were clearly having more impact but Hennessy summoned her resilience and matched her opponent punch for punch in the final rounds.