As mentioned in a previous question, verse is used by some speakers as a verb meaning something like "go up against". This is non-standard. I don't use it this way, so I'm not very familiar with the usage, but if it is a normal verb, I'd expect to hear "verse" after a plural noun but "verses" after a singular noun (as Benjamin Harman suggests).
The standard usage of versus is as a preposition, similar to against. Latin words ending in -us are usually pronounced with voiceless /s/ (as in your transcriptions, /'vɜ:s əs/ and /'vɝs əs/), but for some reason, I believe many American English speakers pronounce versus with a voiced /z/ at the end, /'vɝsəz/, even speakers who don't use verse as a verb. (I don't know whether that pronunciation occurs in British English.)
While Janus Bahs Jacquet has a point about vowel sounds sometimes being elided in fast speech, I certainly would recommend avoiding the use of any pronunciation that sounds like /vɜ:s/ or /vɝs/ because of the possibility of it being heard as the non-standard variant form verse.
Also related: Is 'verse' (or a homonym of 'verse') another word for 'versus'?