Originally posted by Erekose
The book I have on Portorez/Ljubljana has this game annotated by Marriotti and he says at the end simply "Black loses a pawn without any counterplay".
I imagine that he didn't want to play it out against a player of Karpov's caliber as I'm sure it's quite lost. Nonetheless, I suspect a lot of us would play on here, at least for a little while, until the "lost" became a little more obvious to us mere mortals.
I thought about this some more, and I wonder if we here (me included) all say we'd probably play on a few moves simply because the position is new and fresh to us, while the player who resigned had obviously spent a lot of time and energy on the game leading up to the position we have in front of us.
It is very possible, even likely, that black reached the "I'll play on a few moves, take a shot or two" mentality a few moves prior
to the position we have, and resigned when he got to the end of his "few more moves".
It is so different for us, looking at a position in a clinical, sterile environment, compared to the player sitting at the table for a long period of time with a ticking clock under tournament conditions, that sometimes it's hard to relate.
This is one of the advantages of playing through games in a book on a tournament. You can follow a player from round to round, and get a feel for the ups and downs and the flow of events that connects the games together to tell a story.