He defected after the war. He planned to cross the border at East Berlin with Pal Benko. Fuster made it across the border, but Benko was apprehended and sent to prison for nearly three years. Fuster made it to Canada in 1953, settling in Toronto. Fuster won the Toronto City Championship in 1954,1955, 1956, 1962, 1969, and shared it in 1971. Fuster played in many Canadian championships and in 1955 he was Canadian Speed Champion. In 1957, he won the U.S. Speed Championship. He represented Canada in two Chess Olympiads in 1958 at Munich and in 1970 at Siegen. He was awarded the IM title in 1969, following his strong performance in the Closed Canadian Chess Championship. Fuster was a fixture at the YMCA Chess Club and later the Toronto Chess Club where he loved to play speed chess and was known for his willingness of offer advice and encouragement to young players.
The following game was played in the second round of the Portoroz Interzonal when Bobby Fischer was just 15 years old. This tournament was the fourth FIDE interzonal and the first one ever played outside of Sweden. It was a 21-player round robin, with the top six players qualifying for the Bled-Zagreb-Belgrade Candidates (1959) tournament, with the proviso that no more than four players from any one country could advance.
The tournament was won by Tahl (+8 =11 -1), Gligoric was second with 13. Other qualifiers were: Benko and Petrosian with 12.5, and Fischer and Olafsson with 12. Fuster's score was a disappointing +1 -17 =2.
In round two he almost defeated Fischer. Unfortunately, in a promising position he headed down the wrong path with his 26th move and let Fischer escape just when it looked like things might going to fizzle out to a draw. Then disaster struck. His 32nd move was an outright blunder that lost the game.
Had Fuster managed to score the point chess history might have been different. Not for Fuster...he only scored 2 points out of 20 games and another point would still have left him in last place. As it was, Fischer made it to the Candidates by tying with Fridrik Olafsson at 12 points for places 5 and 6. Minus out a point if he had lost this game and a score of 11 points would have dropped him back to tie for 11-13 place with Oscar Panno and Dr. Miroslav Filip.