At the new regime's first training session, Fellaini turned out in white socks, rather than the black variety stipulated by Advocaat, and was immediately sent back to the dressing room to change.
Tension has been simmering since, and the pair were at loggerheads again when Fellaini played the full 90 minutes against Turkey, in Advocaat's first game in charge, then announced he was unavailable against Estonia the following Wednesday, due to a long-standing arrangement to have a troublesome wisdom tooth removed.
Though the Everton midfielder insisted the treatment was urgently needed, after a series of health problems caused by infections from the tooth, Advocaat was so incensed he ordered the Belgian FA to invoke the five-day rule, in an attempt to prevent him turning out against Wolves in the Barclays Premier League the following Saturday.
Advocaat said yesterday: "I still think it was very strange for him to make an appointment like that, and miss a World Cup game, because it was a very important week for Belgium.
"That is still clear in my mind, and I will remember it. Fellaini did not do a good thing for me. Sometimes, these things can happen in football, but, in my opinion, it was not appropriate conduct for a player with a national team.
"It seems to me that there are one or two players in the squad who place themselves above the rest, and I am working to put that right."