Simpson spent the second half of last season working under Keane during a loan spell at Sunderland, impressing so much the former United captain wanted the young defender back at the Stadium of Light this term.

After a chat with Sir Alex Ferguson, Simpson decided to remain at United. But the Salford-born defender saw enough of the Irishman during his time on Wearside to have no doubt Keane will have a major impact in the management game.

quite calm

"Roy Keane is going to be a great manager," said Simpson. "He worked under two of the best managers of all time in Brian Clough and Sir Alex Ferguson, so it would be a bit of a surprise if he hadn't taken anything from people like that.

"He is certainly completely different as a manager than he was as a player. He is quite calm. He thinks about everything. He assessed everything in training. I am sure Sunderland will do well this season."