When Batiatus tells Spartacus of the games that Mercato is planning, he mentions the name Marcus Minucius Rufus; and tells Spartacus that 4 of their Gladiators will be dressed as Roman Legionnaire. Spartacus quickly responds "Our Enemy?" Batiatus continues the conversation explaining that 6 prisoners would be dressed as Thracians. This exchange was most likely a Lexical Ambiguity. Spartacus was speaking from a shocked point of view because he was from the very same tribe that Rufus defeated and still thought him as "His enemy." (So when he said "Our Enemy?" It wasn't a question to Batiatus as to whom he would be facing in the arena; it was a statement of disbelief that he would be put into such a position.)
The battle re-enactment was the first time Spartacus entered the arena as the newly christened Champion of Capua.