"Supergirl vs. Blackstarr" from Supergirl vol.2 #14 (DC, 1983) by Paul Kupperberg, Carmine Infantino and Bob Oksner
When Daring New Adventures of Supergirl wasn't new anymore, and not so daring I guess, it turned into Supergirl vol.2 (from #14-23). If it lasted that long, it's probably because the Supergirl movie would soon come out, but neither the book, nor the film were very good. Because I've only ever had dim memories of the movie, I'd always connected its villain, Selena, with Blackstarr, which I only really knew from Who's Who, though they have nothing to do with one another. The weird connections kids make in their heads.