Zenon Plech's third place in the 1973 World Final at the Silesian Stadium in Chorzów, Poland was controversial.

On the last lap of Heat 19, Soviet rider Grigory Khlinovsky had attempted to pass Plech for the lead going into the back straight.

Despite protests from riders and the Soviet officials, and taking no other eyewitness account into consideration, the referee assigned to the meeting by the FIM simply took Plech's word that Khlynovski had knocked him off his bike.

Had the Russian not been excluded and had been awarded the heat win as many, including World Champions Ivan Mauger and Ole Olsen, believe should have been the case, he would have ended on 13 points.

He was a manager of Polish national team which finished second in the 2001 Speedway World Cup Final behind Australia at Wrocław's Olympic Stadium.