Benko finished 6th (out of 8) with a score of +6 -9 =12 and was involved in a couple of controversies. This was the tournament where he slapped Fischer in an argument over the use of the one second, Arthur Bisguier, that was available to the two U.S. players and he was also involved in a brouhaha involving Paul Keres who finished second with +9 -2 =12.
Benko played a decisive role in destroying Keres' chances of winning the tournament. Keres had beaten Benko 4-0 in the 1959 candidates and in Curacao he was on his way to repeating the performance. Then came the 20th round (out of 28).
Keres slipped up and came within a hair of losing, but managed to escape with a win in a mutual time scramble. Benko, right when he had a perpetual check, knocked over a couple of pieces and exceeded the time limit while putting them back. That was the bare bones story, but it wasn't so simple.
Keres had been the hunt for first place for the whole tournament and his slide began with the Benko game. In horrible time pressure Benko incorrectly sacrificed a piece which left him with nothing better than the perpetual check. With only seconds left on his clock, Benko made the move that forced the perpetual, but his piece was sitting slightly off the square. After he made the move and punched his clock, Keres immediately punched it back and told Benko, ”Adjust your pieces! ” Surprised, Benko let his clock run a second or two before desperately trying to adjust his pieces, but it was too late; his flag fell and he was forfeited.
Although angry, Benko didn't complain and wrote that he thought to himself that he was going to extract revenge by beating Keres when they met again. Then came their final game. It was one of the most important in Keres' career because he was still in the hunt for first. A draw would allow him to conduct a playoff against Petrosian to see who played Botvinnik for the World Championship; a win would make him the outright challenger.
In that final game between the two, the game was adjourned with Benko a bit better. Benko wrote in Pal Benko: My Life, Games, and Compositions that Petrosian and Geller secretly came to him with an offer to help him win the adjourned game against Keres. Benko claimed that he was disgusted by their actions and told them the game would be a draw with best play and demanded that they leave. However, when play resumed Keres made a mistake and lost. That was Benko's story. In Curacao 1962, Jan Timman told it a little differently. Timman reported that it was Korchnoi and Averbach ( one of the Soviet contingent) who had paid Benko the visit and given him some analysis. Benko didn't really need their analysis because he was already one of the world's foremost endgame experts.
Then came the last round and Petrosian was white against Filip who was mired in last place while Keres was playing Fischer. Everything was in Petrosian's favor and it was generally conceded that he would be the winner, but he could only draw with Filip and Keres yielded a draw to Fischer.
There was one game left, Geller vs. Benko, and if Geller won he would tie with Keres for second place. In trying to win, Geller overreached and adjourned in a lost position. Play resumed the next day and Benko, again in time pressure, had to make three moves before the end of the time control and ended up losing on time.
As a result Keres had to play a match (which he won) with Geller to determine second place. Later, Keres claimed that Benko had deliberately lost, in Keres's words, "just to screw me.” Benko claimed that he would never had done such a thing, but Keres, after finishing tied for second with Geller only a half point behind Petrosian, was forever convinced that his one unlucky loss to Benko had cost him a chance for a world championship match. Add to that Keres' belief that Benko had thrown the game to Geller causing him to have to play the tie-breaking match and one can understand his animosity toward Benko.
Regarding this game, while looking at it with Stockfish 8 it appeared that Benko blundered on move 25 when he played 25...Nc3+, but that was not the case! After the reply 26.Kc1 Stockfish immediately gave the correct evaluation of about 6.75 Ps in black's favor.
I am not sure why this is, but this is not the first time I have seen this happen. In any case, when analyzing it's a good idea to have another engine running as a kibitzer!!