Savannah Marshall secured a brutal first round victory in her MMA debut in Newcastle on Saturday night.
The boxing star took on Mirela Vargas in PFL Europe and delivered a dominant performance, with the fight stopped with 32 seconds of the first round remaining and Vargas reeling.
In August, Marshall signed a multi-year deal with the Professional Fighters League just a fortnight after Shields renewed her deal, and the two teased a rematch immediately, though it had not yet transpired.
Shields was cageside to watch her rival secure victory on Saturday, and could be seen picture-in-picture on the broadcast as she clapped the 33-year-old when the fight was stopped.
After the bout, the American stepped into the ring and agreed to take Marshall on in a rematch of their historic boxing bout back in October 2022.
Savannah Marshall (right) secured a dominant first-round win in her MMA debut on Saturday
Boxing champion Marshall signed a deal with the Professional Fighters League back in August
After the fight, she faced off with rival and friend Claressa Shields (right) inside the cage
With Vargas in the centre of the ring late on in the first round on Saturday, Marshall could be seen delivering a number of strong right and left hands as she chased her opponent down.
Vargas appeared to accept defeat and covered up as the blows continued to land, before the referee stopped the bout and Marshall reeled away in celebration.
Marshall took to the microphone post fight, saying: 'These MMA fighters, you've got to be a little bit crazy to do this.'
She added: 'Where's my pal Claressa? That's how you get up off the floor babe.'
Shields then made her way into the ring, and said: 'Good job. You looked worse than me on my debut.'
Marshall responded: 'Oh yeah. Listen, are we getting it on in the cage or what?'
Shields answered: 'I'll fight you in a cage. Why not?'
In October 2022, Shields beat Marshall via unanimous decision at the O2 Arena in London to inflict her rival's only career defeat to date. They have remained good friends since.
Dan Hardy, head of fighter operations for PFL Europe, said in the aftermath: 'Claressa is the next fight we're going to get. Claressa has been very complimentary of Savannah.
'I think Savannah got Claressa's respect tonight, not only what she can do with her hands but how she transitioned into MMA.
Shields was cageside to watch the event and was asked about a rematch under MMA rules
The American inflicted Marshall's only professional boxing loss when the two faced off in 2022
'The obvious thing is for Claressa and Savannah to fight next and I think that's what's going to happen. Claressa has a bit of boxing to deal with and then we'll get that fight locked in.
'My understanding is it's going to be this year towards the end of the year.'
Shields has a record of 2-1 in MMA, winning on debut against Brittney Elkin in 2021 before losing via split decision against Abigail Montes a few months later.
Two-and-a-half years later, in February, she returned, winning against Kelsey DeSantis.