The ground-breaking Italian Cup tie between Sampdoria and Bologna using two referees for the first time had to be stopped last Tuesday due to crowd trouble.

Sampdoria fans bombarded Bologna goalkeeper Gianluca Pagliuca, who used to play for the Genoa side, with everything from bottles to fruit. The match was initially stopped for 12 minutes before the two referees decided to abandon it altogether.

The refereeing experiment, which has the backing of FIFA, is designed to improve the decision-making by the sport's whistle-blowers, who in Italy have been pilloried by the press in recent years.

Each referee is designed to patrol his own half of the pitch, with the two only coming together for dead-ball situations such as penalties, corners and free-kicks, where one will stand near the wall while the other waits by the penalty area.