He was a linesman in the 1934 FIFA World Cup Final, played between Italy and Czechoslovakia in Rome.
[1] Iváncsics, a contemporary of fellow Hungarian referees Gabor Boronkay, Josef Gero and Paul von Hertzka, had already gained vast experience as an international referee in the 1920s, taking charge of matches as far back as 1926 between Italy and Switzerland in Zurich.
[2] He bravely accepted the appointment to the Romania v Bulgaria match in 1929, just after the Hungarian-Romanian conflict.
In the tournament he officiated in four matches, two of which comprised the controversial Spain v Italy quarter-final in which he ran the line to both Louis Baert and Rene Mercet.
He was still refereeing internationals into the Second World War, appointed to the May 1940 fixture between Italy and Germany in Milan.