"The atmosphere at Old Trafford helps. There is a big stimulant for the fans to come to European nights.
"The players also increase their expectation levels to do well in these games."
Lyon extended their lead at the top of the French League at the weekend when they defeated Lille in front of a record French crowd of 78,000 at the Stade de France and Ferguson expects a difficult game.
"There is still work to do," said the United boss. "Lyon have to score and it could be interesting.
"They will try and play attacking football. But we have the bonus of scoring an away goal and played better in the first leg than was suggested. It was not a bad performance."