Let me try to outline what we can know at this point in the discussion.
The OP has asked for a translation of a noun phrase. It is, in particular, an objective noun phrase of the type known in English as a
predicative nominal; the subject and main verb of the sentence of which this predicative nominal must rationally be a part, "he" and "is" respectively, are left unstated. The full sentence here would be:
He is the last man standing. In English, though, the phrase
last man standing has achieved the status of an idiom. Since it is an idiom that we are being asked to translate, I think that we should try to avoid an excess of functional equivalency; our translation should be as directly equivalent as Latin semantics will allow.
The only noun in our predicative nominal is "man", which describes what type of thing the unspoken yet suggested subject "he" is. Since "man" is stated in the original idiom, I think that we should overtly state "man" in the translation.
Said "man" is qualified by the adjective "last", here meaning "remaining after a time period during which a series of events has occurred". I think
@Adrian's
extremus to be a superior adjective to my suggested
ultimus for conveying this meaning.
Ultimus renders the meaning "last in a series", while giving no overt intimation of the passage of time;
extremus, on the other hand, gives a sense of "last after a period of time during which things may have occurred (in the instant case, an arm-wrestling competition)"...it is this second sense that we are looking for.
Regarding verbal action, the only hint of it suggested in the phrase
last man standing is that suggested by the non-finite participle. I would tend to suggest that we try to replicate that in Latin, in order to maintain the character of a predicative nominal. If we introduce a finite verb such as
superest, supervivit, or
superstes, or for that matter even
est, then we sabotage any effort to do that. I suggest, then, that we should let non-finite
stans provide the sole intimation of verbal action in our translation.
Based on the considerations described above, I might suggest
Mas extremus stans as a basic translation, to which
@Tim4567890 can attach something like
ecce at the front, and/or something like
ultra aciem at the back, as he, or perhaps his client, desires. What do you fellows think, especially about the "tenor" of that in the Latin?