Superman overpowers Gilgamesh
Flash beats Makkeri, as the latter will try and make this a speedster fight
Wonder Woman beats Thena
Martian Manhunter and Sersi stalemate, with Sersi transmuting him and Manhunter changing himself back
Ikaris wins a good fight against Aquaman
Ultimus takes Cyborg quite handily
Superman and Ultimus fight into the next round
Wonder Woman takes down Sersi whilst still engaging with Manhunter
Flash and Ikaris goes into the next round
Manhunter and Wonder Woman help Superman and Flash beat the remaining Eternals.
... I have a hard time going against the JLA in any team battle, but that Eternals group is roughly equivalent to the Hyperclan, and there's no weakness to exploit.
I'm honestly not sure if there's any team that beats this group head on.