In Sub-Mariner Issue #59, 1973, Prince Namor, the Sub-Mariner goes to battle with Thor.
When an ally of Namor, who is described by land-dwellers as a ‘mermaid’, is captured by a Russian trawler in U.S. waters, she is transferred to New York to be held under custody of the United Nations.
At UN headquarters, Thor is enlisted to look over Tamara, the ‘mermaid’, who’s being held in a water tank. Namor visits the UN to rescue her but, much to his surprise, he finds Thor watching over the tank.
The two fight it out, taking the battle to the water. Namor can’t compete with Thor’s strength and so he tries (successfully) to remove Thor’s hammer (Mjölnir) from his grip. Thor has 1 minute to regain his hammer or he turns into Donald Blake. Within that time, however, Thor manages to trap Namor in his cloak and throws him many miles out at sea.
Thor wins this one.
