United won just two of their six matches in last season’s competition, with both victories coming over Romanian newcomers Otelul Galati.
Defeat at Basel meant Sir Alex Ferguson’s side finished third in the group and fell into the Europa League, where they progressed past Ajax but were beaten by Atheltic Bilbao in the last-16.
Lindegaard is currently Ferguson’s first-choice keeper, having started ahead of David de Gea in the last two matches against Southampton and Wigan.
The Danish international believes carelessness was part of the problem last season, something which was particularly evident in the home draws against Basel and Benfica.
“We have to do better. Anything else will be very disappointing, as it was last season. I think we got too careless,” he admitted.
The Red Devils face Braga, Galatasaray and CFR Cluj in this season’s Champions League and the three-time winners should have a smooth passage into the knockout stages, but Lindegaard is taking nothing for granted.
“The team you are playing are the champions or among the top three in their respective countries and we have to take every assignment very seriously,” he added.