Borislav ("Bora") Ivkov passed away a couple of months ago, when the blog was down, or I would have blogged about it then. He was a Serbian grandmaster (those of you who remember him probably think of him as a Yugoslav player, and indeed, he won that national championship three times before the country disintegrated), a Candidate in 1965, and the first World Junior Champion back in 1951. He defeated five World Champions, and at one point had an undefeated 3-1 score against Bobby Fischer. (That ratio didn't last, to put it mildly, but that he had it at one point is impressive!)
There's a good summary of his career on his Wikipedia page, along with links to 15 notable wins, almost all of them against World Champions and other Candidates. The link to the Benko game isn't working, so I give the game here, along with both of his wins against Fischer. (Only one of the Fischer wins is linked in Wikipedia, so I've supplied the second as well. Coincidentally, in both games Ivkov is Black and has rook and knight vs. rook and bishop. Further, in both games Ivkov offers the swap of his rook and knight for Fischer's rook to promote a passed pawn. It would have been an extra-fun coincidence if the first game had gone one move longer or the second one move shorter [but not both], in which case they would have gone the same number of moves.)
Rest in peace.