Spare part for outlet under the sink: plug does not go up

Good day!

Does anyone know what the part marked in red in the photo is called? It normally fits where the arrow is. You lift or lower the stopper with it. The rest of the rod, that is, before the white ball, is completely rotten and gone. Therefore, the stopper can no longer be moved. For me, just this rod with the white ball would be enough. The whole thing is located under a washbasin from the "Virto" series by Keramag, year of manufacture 1999.

Thanks, Matthias says!

Try it with the term eccentric rod.

Look at that - that's exactly it! I would never have thought of that. Matthias says thank you very much!

Just as a side note. If the chrome pipes are already rusting on the outside, then you should replace the entire siphon. You can expect something to leak there any day. I have already replaced 2 pieces after 18 years in my case.