No play was possible at the French Open on Monday because of rain.
It is the first time since the same day 16 years ago that not a single ball has been hit in anger for a whole day at Roland Garros.
The tournament has been blighted by poor weather this year but there have been enough dry spells to keep things broadly on schedule.
That changed on Monday as rain delayed the start of play and, with the forecast poor for the rest of the day, organisers decided to cancel all play at 1.40pm local time.
The first two men’s quarter-finals are also on the schedule for Tuesday, with Andy Murray due to play Richard Gasquet and defending champion Stan Wawrinka taking on Albert Ramos-Vinolas.
One day lost to rain is not a major headache, but the worry is the forecast is not good for much of the rest of the week.
All the fourth-round matches in the bottom half of both draws were completed on Sunday apart from the ones between second seed Agnieszka Radwanska and Tsvetana Pironkova and former finalists Simona Halep and Sam Stosur.
But the top halves were due to play on Monday and are now at a significant disadvantage.
For the men playing best-of-five-set matches, playing two days in a row is far from ideal, but that is now the scenario facing the likes of Djokovic, David Ferrer, Tomas Berdych and Dominic Thiem.
Organisers will desperately hope the delayed matches are able to be completed on Tuesday, but the forecast indicates that is probably unlikely.
The French Open is now the only grand slam without any covered courts, with the roof over Arthur Ashe Stadium in New York due to be operational for the first time at this year’s US Open.
The Australian Open has three covered courts while Centre Court at Wimbledon acquired a roof in 2009 and Court One will be covered from 2019.
Plans for the redevelopment of Roland Garros, including a roof over Court Philippe Chatrier, were first drawn up in 2011 but organisers have become embroiled in a planning dispute.
Local residents and environmentalists have objected to plans to expand the cramped site into the neighbouring botanic gardens and the project is now not expected to be completed until 2020, with the roof the final part of the jigsaw.