The first GP3 race at Monza has been postponed until Sunday morning and the second race has been cancelled due to the delays caused by poor weather conditions.
Heavy and persistent rain caused Formula 1 qualifying for the Italian Grand Prix to be suspended by more than two and a half hours, which meant the start times for the support races that had been scheduled to take place afterwards were pushed back.
The GP3 first race had been due to get underway at 1750 local time, but with the rescheduled Formula 2 race not set to get started - assuming there are no further rain delays - until 1820, the decision was taken to postpone the event until tomorrow morning.
The torrential weather at the northern Italian track had already caused GP3 qualifying to be cancelled first thing this morning, with the grid for race one being set by the outcome of yesterday's practice session.
That meant Honda F1 junior driver Nirei Fukuzumi claimed his first GP3 pole as a result of setting the fastest time in practice.
The Japanese driver will start what is now the only race of the weekend for the third-tier category ahead of his ART Grand Prix team-mate, and Mercedes F1 junior, George Russell.
Jack Aitken, second in the championship standings behind Russell entering the weekend, will line up fourth, with Anthoine Hubert in third.