Finding an obscure item at the precise time I needed it

Earlier this year I discovered that the plug chain in the bathroom sink had become separated from the back of the sink. Unfortunately the small metalic triangular piece of metal that connects the chain to the back of the sink was missing. So I walked to a nearby Tesco's to see if they sold any sink plugs and chains just so that I could replace it. As I approached the entrance to the store I spotted an identicle connector to the one that I needed just lying on the ground all on its own. No chain or plug, just that one little piece of triangular metal. I wonder what the odds are of finding that obsure single item, all on its own, at the precise time that I was going to try to find one to buy. I had never ever found one before during my 65 years and it was the first time that I had ever needed one. I don't even know how to begin to rank the magnitude of this coincidence in any meaningful way.