Dick Advocaat has suggested that the lack of quality among the Sunderland squad led to his decision to leave the club just eight games into the Premier League season.
The Dutchman initially decided against signing a permanent deal at the Stadium of Light after clinching survival with the team last season.
The 68-year-old made a U-turn and penned a contract with the club, who signed eight new players in the summer transfer window, but he decided to cut short his spell at the weekend.
"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 in style," Advocaat told Studio Voetbal. "I think it was time for someone else to take over at Sunderland. I became negative and that didn't feel like myself.
"I don't regret signing my new contract because it was a great experience. 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."
Sunderland are yet to win a league game this season following five defeats and three draws.
Danielle Joynson
