Natasha Jonas suffered the first defeat of her professional career after succumbing to a fourth round stoppage against Viviane Obenauf at the Ice Arena in Cardiff. (photos by Lawrence Lustig).

Obenauf (13-4, 7 KOs) fought Jonas’ former Great Britain podium squad team mate Chantelle Cameron in her last fight in December, where she was forced to retire in the sixth round, but she wouldn’t quit in a determined effort against Jonas, who slumps to 6-1 (5 KOs) and hands over her WBA international super-featherweight strap.

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Jonas, known as ‘Miss GB’ from her time on the British Olympic squad in 2012, shrugged off an awkward but aggressive attack from Obenauf in a fast-paced first round.

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The Brazilian charged forward and bullied the Briton into the ropes with a series of swings, which had some effect, despite not many of those punches landing clean, in the opening two rounds.

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However, Obenauf fired with much more success in the third as the two wrestled in what was turning into a brawl.

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The fighting in a phone booth style favoured the 31-year-old Obenauf as Jonas slipped under a relentless barrage before falling a second time onto the seat of her pants following a ramrod left hook.

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Another sharp left floored Jonas in the fourth and she couldn’t cope as she was dazed after a combination of ruthless, thudding blows that forced trainer Joe Gallagher to throw in the towel.

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