"He won the competition first."
Can I see the ordinal number "first" as subject complement?
Thank you!
First in this context is an adverb.
Wikipedia defines subject complement as being "a predicative expression that follows a linking verb (copula) and that complements the subject of the sentence by either (1) renaming it or (2) describing it."
Basically, giving detail to the subject.
First is not giving detail to the subject, it is giving detail to the verb.
Here is an example of a subject compliment:
"He was the first to win the competition."