Savannah Marshall has signed professional terms with Floyd Mayweather – and already provoked the ire of double Olympic champion Claressa Shields.

Marshall remains the only fighter to have defeated the otherwise all-conquering Shields, outpointing her en route to becoming the world amateur champion in 2012.

The 25-year-old announced her decision to leave the Great Britain squad in March having failed in her second attempt to claim an Olympic medal in Rio last summer.

Marshall will predominantly base herself in Las Vegas to work with Mayweather’s promotions company, and plot a potential big-money re-match with Shields.

Shields has won her first two professional fights and in March made history by becoming the first female fighter to top a premium TV card in the US.

But she was less than impressed by news of Marshall’s deal, tweeting: “The best news I’ve heard in a while! Her ass is kicked! @MayweatherPromo set it up!”

Shields later added: “Mannnnnnn he (Mayweather) just added fuel to the fire man! I’m going to light her ass up! Right in front of him!”