Det här är förmodligen en kort historia " Arena " av Frederic Brown .
Som nämnts i @ beichsts svar kallas också en episod av Star Trek TOS Arena skrevs med slående likheter med denna novell, även om den inte var avsedd för den här novellen att ligga till grund. Brown fick senare krediten för telefonspelet.
Den har en galaktisk kamp mellan mänskligheten och en mystisk tävling som heter "The Outsiders" när en annan ras av större makter ingriper!
Här är en del av sammanfattningen av Wikipedia, jag har markerat de viktiga bitarna i frågan:
The mysterious Outsiders have skirmished with Earth's space colonies and starships. Their vessels are found to be faster and more maneuverable, but less well armed. There have been no survivors of the small raids on Earth forces so Earth has no information about the Outsiders. Fearing the worst, Earth builds a war fleet. Scouts report a large armada approaching the solar system. Earth's defenders go to meet them. All indications are that the two fleets are evenly matched.
Bob Carson is the pilot of a small one-man scout ship on the outskirts of the fleet. While engaging his Outsider counterpart in battle, he blacks out. When he awakens, he finds himself naked in a small enclosed, circular area about 250 yards (230 m) across. ..
Carson hears a voice in his mind that identifies itself as the end product of the evolution of an entire race. While traveling through various spaces and dimensions, it had come upon the impending battle. The evolved intelligence decided to intervene because both humans and Rollers have the potential to one day evolve into a being like itself, but the upcoming war would utterly destroy one side and hurt the other so badly that it would not be able to fulfill its destiny. It therefore chose one individual from each species to fight in this small arena. The loser will doom its kind to instant extinction.
Carson and his opponent discover, through trial and error, that there is an invisible barrier between them, and that living things cannot cross it, though inanimate objects can. Carson tries to communicate with the Roller, to see if a compromise is possible, but receives a mental message of unremitting hatred.