The Black Cats are now on the hunt for the Dutchman's successor.
The Dutchman’s departure was confirmed this weekend after the Black Cats’ draw with West Ham and he leaves the club in 19th place, with three points from their first eight games.
Speaking on Studio Voetbal, a programme from Dutch broadcaster NOS, the 68-year old said:
"I already made my decision last week, but the club asked me to do the match against West Ham and I really wanted to finish this in style.
“The struggle against relegation is not my cup of tea. I think it was time for someone else to take over at Sunderland.
“I became negative and that didn’t feel like myself,” he added.
Advocaat was brought in initially as a stop gap last season but his exploits prompted the club to offer him a longer term deal and he insisted there are no regrets over his decision calling his time on Wearside a ‘great experience’.
The lack of quality in the Sunderland squad is clear to see and Advocaat hinted at a lack of transparency between him and the chairman Ellis Short over their approach to transfers this summer.
“Our squad was simply not good enough… The club knew that we had to strengthen ourselves, but the chairman never told me how much we could spend.”
His frustrations over the failure to significantly strengthen the squad undoubtedly played a major role in his decision to walk, and whoever takes the reigns now has the unenviable task of turning the tide at the Stadium of Light.