Photos: Open workout featuring Shields, Marshall, Mayer, Baumgardner

The bad blood hit the seas Wednesday afternoon.

The open workout for Saturday’s all-female card at London’s O2 Arena (ESPN+, 2:30 p.m. ET/11:30 a.m. PT) was conducted on a boat that was sailing along The River Thames. The top of the bill sees middleweight champions and one-time amateur adversaries Savannah Marshall (12-0, 10 KOs) and Claressa Shields (12-0, 2 KOs) battle for the undisputed title.

In the co-feature, American stars Mikaela Mayer (17-0, 5 KOs) and Alycia Baumgardner (12-1, 7 KOs) will tangle for the WBC/WBO/IBF/Ring Magazine junior lightweight titles.

The combatants faced off in the ring on the top floor of the boat, the partly cloudy London skies providing a suitable backdrop for the occasion.

Here are photos below of the open workout: