The word "more unrivalled" is already a superlative form, meaning there is no other term to use that means a higher level of excellence or superiority. However, if we were to consider antonyms of "unrivalled," we would consider words like "common," "average," "mediocre," or "ordinary." In other words, something that is unrivalled is unique and exceptional, while its antonyms would represent the opposite - something that is typical or unremarkable. Therefore, it's important to understand the context of the word "more unrivalled" to appreciate its significance, which often refers to something that is beyond comparison and unmatched in its class or category.