Dick Advocaat has stepped down as head coach of Sunderland, the Premier League strugglers announced on Sunday.
Advocaat, 68, was appointed last March and successfully steered Sunderland clear of relegation, but they have made a poor start to the current campaign and sit second-bottom with three points from eight games.
"I want to thank everyone who has stood behind me," Advocaat said in a statement released by the club.
"This is a very special football club, with so many great people, but I feel it is the right time to do this -- not for me, but for the club.
"I have made the decision to go after only eight games as I felt it was important to give everyone time (to) turn things around -- like we did last year.
"I am thankful to the chairman (Ellis Short) for understanding my feelings and I remain on good terms with everyone at the club."
The experienced Dutch coach announced his departure from Sunderland at the end of last season, following a 0-0 draw at Arsenal that secured the club's top-flight status and left him in tears.
He reversed his decision in June, signing a one-year contract, but Sunderland have made a dismal start to the new season and Advocaat hinted after Saturday's 2-2 draw at home to West Ham United that he had decided to leave the Stadium of Light.
"I am truly saddened by Dick's decision, but I respect him for his honesty and for doing what he feels is right for the club," said Sunderland chairman Ellis Short.
"He is a man of integrity and a true football person."
Short added: "It is also testament to his character that he has forgone any kind of a financial settlement, something which is very unusual in football."
Former West Ham manager Sam Allardyce and Burnley manager Sean Dyche have been installed as the early favourites to succeed Advocaat, who has also managed teams including Holland, South Korea, Belgium, Russia, PSV Eindhoven and Rangers.
British press reports claim that sporting director Lee Congerton has also tendered his resignation and is working a period of notice.
Advocaat, whose assistant, Zeljko Petrovic, has also left the club, added: "I wish Ellis, Lee, all of the staff, players and of course the supporters, who made me feel so welcome here, the very best of luck for the rest of the season.
"I have some wonderful memories to take with me and I hope I will return to see everybody again in the future."