Times Book Of Cryptic Crosswords

[barnaclebill58]

I would be grateful for the parsing of these.
Sets competition record , holding a 21 up. Ans Davis Cup (=sets competition). The ans to 21 is "five" = "v" but where does the daiscup come from please?
Muster resources, being down in the dumps. Ans recycle (= going to the tip) but how does muster resources fit, please?
Avoiding company cutting reliable duet for performance. Ans solitude.
An intro to Aristophanes' Lysistrata, half written, in study. Ans analysis. I can see "lysis" and "a" from Aristophanes but where does the missing na come from, please?
Found union membership that's expedient. Ans Married off. Union membership is marriage but that's as far as I can get.
Male celebrity initially sounds confused in racing vehicle. Ans Stock car. I can see star around ockc but can't see how to get those letters.
I solved the FT crossword without aids yesteday but all the crosswords in this book seem much much harder than many of the recent Times Crosswords.

[Mamyalynne]

An intro to Aristophanes' Lysistrata, half written, in study.

An A(ristophanes) Lysis(trata)

[Mamyalynne]

Avoiding company cutting reliable duet for performance.

Soli(d) (reliable,cut) + anag. duet

[Lie-in King]

Davis Cup - 'disc' (holding) 'a V' + 'up'

[Mamyalynne]

Sets competition record , holding a 21 up.

A V in Disc + up

[Lie-in King]

Stock car - with initial sounds confused is "co ck star" (space is for the site filter)