Marcelo Bielsa has resigned as head coach of Marseille just one game into the new Ligue 1 season, having lost 1-0 to Caen.
The Argentine tactician has been with OM since 2014, guiding them to a fourth-place finish last campaign, but has abruptly left after the defeat at Stade Velodrome.
"I have resigned from my post as manager of Marseille," he announced at his post-match press conference. "I am sad and frustrated. I cannot accept the situation of instability at the club.
"I have finished my work here, I will return to my country. I thank the fans for always being behind me during games and on a daily basis."
The former Argentina, Chile and Athletic Bilbao boss follows star players such as Andre-Pierre Gignac, Andre Ayew and Dimitri Payet out of the club.
Before announcing his departure, the 60-year-old had his say on the match, in which Andy Delort scored the winning goal for Caen in the first half.
"We had a dozen scoring opportunities," he said. "With so many opportunities we must win. There are no excuses for this defeat."