A Face-palm for Sauron

[Findegil]

I imagine that when the ring was taken by Isildur Sauron was in panic and winged away into hidding. I assume that the physical fight with Gil-galad, Elendil and Isildur had gone badly for Sauron and that Isildur was able to withhold the ring physically from Sauron at that moment. Further I think that when soon after Isildur claimed the Ring as his own instade of throwing it into the pit of doom that this act allone brought Sauron the loss of power we observe.
This loss of power for Sauron in this down fall (the overall event) was terrible (for him). It is mention a few times that Sauron was in doubt about the ring and its existence. Maybe he recognised only when Frodo claimed the Ring, as a kind of a reminder, that what had happend in the Second Age was like a birthday party against what was possible with the destruction of the ring.

I don't think that Sauron did consider what the loss of the Ring to some other Lord or the destruction of it would mean for him when he made that Ring. Consider Celebrimbor, he also found out too late how much of his inherent power had gone into his three Rings when Sauron had bound it up with the one and Celebrimbor could nolonger destroy his own creations even with the help of Galadriel.

Respectfully
Findegil