When does one use the perfect of possum? I can’t think of any case where being able to is punctual.
Januam aperire potui.
I was able to open the door.
At Miloni ne favere quidem potui… (Cicero, Oratio XVI, In M. Antonium Philippicarum, §9)
“But I could not (/was not able to) at all be behind Milo…”