Marshall and Shields are engaged in one of boxing’s greatest rivalries with the Briton winning at amateur level and the American avenging the defeat – the only one of her career – in 2022.
Marshall said a big reason behind her move to the PFL was to chase a third fight with Shields after her rival made her MMA debut in 2021, with “boxing politics” preventing a trilogy fight happening in the ring.
After Marshall defeated Vargas, television cameras showed Shields smiling and applauding at ringside, before the pair shared words and a respectful fist bump in the cage.
“I just said to her ‘are we going to get it on in here or what?’ And she said ‘hmm yeah’,” Marshall told BBC Sport Teesside.
“I hope so, but it was a shady yeah. We’ll have to see.”
Shields, meanwhile, said the pair will fight under MMA rules, but she’s unsure when it will be.
Undisputed middleweight champion Shields is set to face Vanessa Lepage-Joanisse for the unified light-heavyweight championship on 27 July.
“As of right now I’m the better MMA fighter and it still stands that Savannah just punches harder,” said Shields.
“But I have strong points she doesn’t have and she has weaknesses that I can take advantage of right now. So the fight’s going to happen – I just don’t know when.”