Manchester United boss Louis van Gaal has hinted of a frosty relationship with Chelsea rival Guus Hiddink.
Van Gaal may be expecting a tough test against Hiddink's side at Stamford Bridge but was unwilling to engage in conversation about his fellow former Dutch national boss at his latest press conference.
The pair are two of Holland's most successful managers of recent times but are not close.
Asked what his past dealings with Hiddink were like, Van Gaal said: "Professional."
In the past, Holland international Wesley Sneijder has described Van Gaal as a "tough schoolteacher" and Hiddink as a "friendly uncle".
Van Gaal was also unwilling to comment on those remarks.
He said: "It is his feeling. When he says that it is his feeling."