West Ham United manager Slaven Bilic has said that the Premier League "will be worse off" without Dick Advocaat.
The Dutchman stepped down as head coach of the Black Cats on Sunday, with Saturday's 2-2 draw against the Hammers being his last game in charge.
Advocaat opted to step down after Sunderland failed to win their opening eight games of the season, and Bilic has admitted that he is disappointed to see the 68-year-old leave.
"I told him I would like (him) to stay. You saw on the touchline he is a man full of energy and passion. The Premier League will be worse off without him," Bilic told West Ham's official website.
"He is a man of knowledge, and his experience at different clubs in different countries and at international level is unbelievable.
"It's his decision, only he knows what he feels. For a man of his experience, he's basically done everything in different countries, at international level. Only he knows but I rate him so much, there aren't many managers like him."
Advocaat has also managed the Netherlands, PSV Eindhoven, Rangers and Zenit St Petersburg during his career.