No doubt "Friendless" had been clued in a great variety of other ways, but as far as this idea goes, fair play to the setter for trying something knew with "Sat".
Socially isolated, not stopping at the end of the day [Times 24132]
Presumably Saturday never comes for such as Billy-No-Mates [Times 24011]
The weekend never coming makes one unable to be with mates [Times 25220]
Why Saturday never comes alone? [Guardian 26960 - Paul]
Lacking pals with the weekend never coming it seems [Guardian 14510 Bradman]
Alone so the weekend never arrives? [Telegraph Toughie 1136 Dada]