Louis van Gaal has branded fellow Dutchman Edwin van der Sar a "manufactured goalkeeper".
The pair go head-to-head in the Allianz Arena on Tuesday night 15 years after Van der Sar was part of Van Gaal's Ajax side that claimed Champions League glory at Juventus' expense.
Little could the current Bayern Munich coach have known the keeper he helped develop would stand in his way of a semi-final berth as he approaches his 40th birthday.
Van Gaal's assessment was not exactly the greatest compliment, but the Bayern boss insists he is correct, and said: "I always say Van der Sar is a manufactured goalkeeper.
"He is not so happy when I say it, but there are more natural goalkeepers in the world. He always works with his brain. That is his secret. He is a great role model for goalkeepers around the world."
Van Gaal will no doubt be hoping the Manchester United keeper forgets a few things on Tuesday as Bayern look to better their stated aim of a place in the last eight.
The hosts are sweating on the fitness of former Chelsea star Arjen Robben, who aggravated a groin injury in Saturday's defeat by Stuttgart, and Bastian Schweinsteiger is suspended, but Franck Ribery is expected to play despite being plagued by an ankle problem recently.
There is a hint from the German camp that Bayern would be happy with a goalless draw ahead of next Wednesday's Old Trafford decider.
However, Van Gaal insists there is no sense of inferiority amongst his squad, especially concerning Wayne Rooney.
"I never have fear and my players don't have any fear either," said Van Gaal.
"We value Rooney's quality. He is a super footballer. When he was younger, I often wondered whether he had the vision in his game. He has developed that now and is very hard to mark out of the game.
"But we can manage because we also have quality. Ferguson and his players should be scared of that."
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