Terri Harper has vowed to prove to Caroline Dubois that her psyche has been transformed since her most recent defeat in March 2024.

Harper and Dubois on Sunday at London’s Olympia contest the WBO and WBC lightweight titles – Harper brings into the contest the title of the WBO – when, by her own admission, Dubois will seek to capitalise on the psychological weaknesses she believes her fellow Briton to possess.

The 29-year-old Harper lost to Sandy Ryan in 2024, and to Alycia Baumgardner in 2021, and having been confronted by the most aggressive Dubois most have seen she has accused her rival of being a “bully”.

An overhaul to her daily routine and fight preparations has, however – according to Harper – made her a considerably stronger figure than she believes Dubois is aware, and she is convinced that she is therefore being underestimated.

“If this fight was a couple of years back there’s no way I’d have the self-belief that I have today,” she told BoxingScene. “It’s the experience thing, but a little bit more maturity and just self-development as well.

“Over the years you realise it’s your job; it’s the sport you chose to do; I do generally love it. Working on my mindset as well as my physical fitness has been the key for me the last couple of years. I was very present in the open workout, whereas [previously] my mind would have been wandering and drifting off. For the first time, only the last couple of fights, I’m ready to just get in the ring and do the business.

“Meditation; self-belief; taking time for myself and switching off. I’ve booked an Airbnb away from the fight hotel so I can switch off; you’re not getting caught up on social media; all the outside noise is not for me. I’m here to do one job and that’s Sunday night.

“It’s helped with things like my rest; my mental preparation. These weeks are big weeks – they’re draining and they zap your energy. Just nipping over to the hotel lobby to get picked up zaps your energy. It’s something I wish I knew sooner in my career but you live and you learn.

“It’s about controlling [nerves] – you’re not human if you don’t have nerves. Nerves 100 per cent help with your performance, and it’s now I know how to use them to my advantage.”

Harper, a three-weight world champion, was asked whether the widely admired Dubois, 25, represents her toughest opponent to date, and she responded: “I’m not daft – she’s a great fighter. I’m in with a great fighter, and it’s gonna be a tough fight – it’s my toughest fight to date – but I’ve got full confidence in the timing of everything, and the timing of my career. It’s perfect.

“She’s not a world champion for nothing. She’s young. She’s explosive. But I’ve just gotta go there, focus on myself, do what I’ve been working on – everything is under my belt and ready to use on the night.

“The trash talk [is a strength of hers]. If you’re weak, mentally, I can see how she would get to you – and she’s got the [amateur] pedigree. But she’s not been tested as a professional.

“She’s too emotionally invested. To be fair, it’s probably not a bad thing, ‘cause it shows how much she wants it. But getting caught up in petty arguments online and stuff like that – it’s taking attention away from the fight.

“I know for a fact she’s gone off my Sandy Ryan loss; my Hannah Rankin performance [the victory of 2022]. To be fair, if I were Caroline watching them I’d think ‘Yeah – it’s a walk in the park this one’. But I’m glad she’s thinking that, if she is.

“[The bravado is] fake. I can see straight through it – that’s why everything’s over my head. She knows she’s in a tough fight.”