Sami Hyypia's side began their return to the Champions League with a disappointing defeat at Old Trafford, making several mistakes as the Red Devils ran out easy victors.
However, their skipper believes his team can play far better and has urged them to cut out the careless errors in future matches.
"We can play a lot better than we did," he told reporters.
"We played well in parts, but we didn't manage to maintain that level of performance throughout the 90 minutes.
"Had we been able to do so, we may have caused Manchester United a few more problems.
"We were in with a shout at 2-1, but we brought the third goal upon ourselves. We can't afford mistakes like that."