Borussia Moenchengladbach coach Marco Rose admitted Monday that it would be "more than extraordinary" if his side were to overhaul a 2-0 deficit and knock Manchester City out of the Champions League.
Gladbach face City in Budapest on Tuesday for the away leg of their last-16 tie, and the crisis-hit Bundesliga club need a near miracle to reach the last eight against the Premier League leaders after losing the first game 2-0.
"It would be more than extraordinary -- it would be a sensation," said Rose.
City's quality and the two-goal deficit meant it would be "unbelievably difficult" for Gladbach, the coach added.
"We don't want to give the impression that this is a friendly. It's a Champions League game where we have a chance of reaching the next round, but we have to be realistic," he said.
"We want to put in a good performance and then come home and concentrate on our essential tasks."
Gladbach have slipped to 10th in the Bundesliga after a dramatic collapse in form since Rose announced his intention to join German rivals Borussia Dortmund at the end of the season.
They have lost six games in a row in all competitions since mid-February, leading many fans to call for Rose's resignation.
After a 3-1 loss to Augsburg last Friday, the Gladbach coach suggested that he would rather have a full week of training than play in the Champions League against City, a comment on which he attempted to row back on Monday.
"Of course the City game is important to us," said Rose.
"On the other hand, if I had said that I have full confidence that we can go there and turn it around, then everyone would have shaken their head and said Rose has lost his marbles," he added.
He added that City had overtaken Champions League holders Bayern Munich as "the best team in Europe".
Pep Guardiola's side have shaken off their recent derby defeat against Manchester United to return to winning ways with thumping victories over Southampton and Fulham in the last week.
The Premier League leaders remain firm favourites to reach the last eight against Gladbach, as they chase a first Champions League title and an unprecedented quadruple this term.