Among Mr. Unzicker 's notable results were a tie for first place with Boris Spassky in 1965 in the Chigorin Memorial at Sochi , the Black Sea resort in what was then the Soviet Union ; first place in 1967 at Maribor in the then Yugoslav republic of Slovenia , ahead of Samuel Reshevsky ; and a tie for fourth place in 1967 in the Second Piatigorsky Cup in Santa Monica , Calif. , ahead of Tigran Petrosian , then the world champion .