Ferguson made the challenge when first taking charge of Manchester United.
Slot is now on the brink of delivering Liverpool the Premier League at first attempt and said: “What is the perch?
“Ah, okay. That would be nice...”
The Dutchman leads Liverpool today against Tottenham, with a draw being enough to confirm the Reds as champions.
"It is for other people to judge me,” said the Dutchman. “It would be a bit weird to judge myself. I can judge the performance for my staff and the medical staff - and they should get a lot of credit.
“We had our injuries, but that’s what every team has because you can’t go through this league without injuries because the schedule is too much.
"We were always able to perform at our standards in terms of physicality, so that is a very big compliment to the medical and performance staff. And the tactical staff is also part of that process.
“Maybe I will judge myself at the end of the season and see if I can do better. But to do it in public would just be a bit weird.”