Final answer:
The noun clause "That Auburn has won this many games so far" serves as the subject of the sentence. This type of clause can carry out the function of a noun, ensuring the verb agrees with it just as it would with a single noun.
Step-by-step explanation:
The noun clause in the sentence "That Auburn has won this many games so far is a miracle" acts as the subject of the sentence. The entire clause "That Auburn has won this many games so far" is the subject, which performs the action of being a miracle. In terms of subject/verb agreement, it is important to identify the core noun or clause that the verb aligns with. Just like the sentence "The play comes highly recommended", despite any additional phrases, the verb must agree with the singular subject "play". In our example, the verb "is" agrees with the singular noun clause.
Furthermore, in sentences where clauses function as the subject, such as "To attend a party without pants is quite foolish" and "Running a marathon is his idea of a vacation!", they ensure subject-verb agreement even though the subject is not a single noun, but rather a phrase or clause.