They will be in next week's draw alongside Barcelona, Villarreal, Bayern Munich and Porto, with Italian representation conspicuous by its absence.
"It should temper some of the expectations of a lot of Premier League teams," said Megson of the big four's dominance of Europe.
"When you look at what we are playing against week in, week out, Real Madrid (against Liverpool) can't handle it, Inter Milan (against United) can't handle it.
"The Premier League is the strongest league by a street and when Liverpool play as they did the other day that is how we are playing against them all the time.
"If Madrid can't handle it that shows how difficult it is for the rest of us."
Megson said the vast wealth of the Premier League had made such domination possible.
"It's money, pure and simple. If the money wasn't here the foreign players would be playing in their own countries," he added.
"It is a big draw as it is in every walk of life and we have got the wealthiest league in the world, so it attracts the best players in the world.
"We have to realise how impressive the Premier League is to the rest of the world."
, Draw 9/4
, Fulham 13/5