When asked whether he was concerned United would not qualify for next season's Champions League, the Scot replied: "The players here are good enough. The end of the season is when you have to be in your best form.
"Over the years Manchester United have been slow starters quite often. We have been a little bit slow at the start again but hopefully that will improve.
"We knew we had a difficult opening period and we knew the games we were coming into looked more winnable, but we have got to do it. We will pick ourselves up."
United, who along with Shakhtar Donetsk are joint top of Group A in the Champions League, play host to Real Sociedad on Wednesday.