Maybe he was popping adderall or developing some sort of brain tumor that has given him amazing chess skills.
Perhaps, working late in the laboratory, he was bitten by a radioactive, chess-playing spider.
http://www.bestpsychologydegrees.org/10-people-who-gained-extraordinary-abilities-from-brain-damage/
I'm not denying that such things occur but it's still clutching at straws.
Would also make life more difficult for opponents with web all over the board.