Charles Leclerc ended a sodden first practice session for the Italian Grand Prix at the top of the timesheets as red flags interrupted the session no fewer than three times.
Kimi Raikkonen's spin into the wall at Parabolica forced a first delay, with Sergio Perez then damaging both the front and back end of his Racing Point at the Ascari Chicane while on an out lap once action resumed.
Pierre Gasly also stopped on-track to prompt the red flags, but he was able to reverse back onto the asphalt after getting beached on the kerbs at the first chicane and the delay was minimal.
Mercedes spent most of the session in the garage, unwilling to risk damage, but Lewis Hamilton and Valtteri Bottas emerged late on as the track began to try and seemed to be practising towing each other down the main straight as they plot tactics to eat into Ferrari's enormous straight-line advantage in Saturday's qualifying, when the weather is expected to clear up.
Several teams did emerge on slick tyres at the end of the session, and Leclerc's final lap was enough to start the weekend with a Ferrari at the top of the timesheets, just edging out the McLarens of Carlos Sainz and Lando Norris.