United, who will be missing injured striker Wayne Rooney, have won just one of 18 away games against Spanish opponents, with eight draws and nine defeats, and failed to score on their last three trips to the Iberian nation.
"It's always the hardest place for us to go if you give me that statistic," Ferguson said at a news conference at Valencia's Mestalla stadium on Tuesday.
"The standard of Spanish football has always been very, very good. It's a difficult place to win, there's no doubt about that.
"That's the great thing about the European Cup. You always get to play against fantastic teams in Spain, Italy and Germany. That's what makes it such a great tournament."
Valencia, Champions League runners-up in 2000 and 2001, have made a bright start to their La Liga and European campaigns.
They top the domestic standings after five matches, ahead of Barcelona and Real Madrid, and thumped Turkish champions Bursaspor 4-0 in their opening Champions League group match.
United floundered to a 0-0 draw at home to Rangers on their European debut this season and were held 2-2 at Bolton Wanders in the Premier League at the weekend.
"Valencia's home record over the years has been very good and we respect that," Ferguson said.
"They're very strong defensively and they don't surrender anything easily.
"Hopefully we can impose ourselves tomorrow the way we know we can."
The 68-year-old Ferguson said he would delay his decision on whether to include Rio Ferdinand in his starting lineup against Valencia until Wednesday.
The central defender is returning from a knee injury and played against Rangers but missed the Bolton trip.
"He's much fitter now but probably needs another game or so," Ferguson said, adding that he had no complaints about the recent performances of Jonny Evans and Nemanja Vidic.
"It's a decision I'll take tomorrow about whether he (Ferdinand) starts or not but we're looking forward to having him back."
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