David Bentley -- the first Englishman to play in the Russian Premier League -- believes Manchester United could come undone at his former club FC Rostov if they are complacent.
A sell-out crowd will greet United for the first leg of their Europa League round-of-16 tie at the Olimp-2 stadium -- an uncompromising venue where Bayern Munich and Ajax have already lost this season.
Thursday will see Jose Mourinho's men become the first English club to face Rostov on the European stage, and Bentley says they can't take their opponents for granted.
"Fifteen months on from doing my knee on loan at West Ham, I was looking to get away from England," the former Arsenal, Tottenham and England winger told Press Association Sport.
"My agent said, 'Look, Rostov, a team in Russia, have come forward.' The chance to be first Englishman to play in Russia was really the thing that excited me -- a unique experience.
"It was good in Rostov. The people there were professional and helped me out. Nice people. All the preconceptions you have of Russia go out of the window. It is quite a nice place.
"The ground is like an old English stadium. It has got one sort of main stand, one behind the goal and the rest is sort of at lower-tier stadium. The new one for the World Cup looks amazing but, yeah, the stadium will be a difficult place for Manchester United.
"They can't underestimate the team for one minute. They have done well, beating Bayern, and no-one really knows them."