Man Utd boss Ferguson wary of new emerging Euro powers
Ferguson, who takes his team to Basel on Wednesday needing a point to reach the knockout stages, said: "It's true we could have only one team through, and it represents a different challenge for English clubs.
"We have to make sure we don't underestimate the group stages.
"There is a change in terms of the money the Russians have got, and even a club like Apoel Nicosia have got, to bring in foreign players. Wealth is playing a part in that respect."