Ryan Giggs says it's important United don't dwell on Saturday's disappointing result against Bolton Wanderers.
The Reds couldn't find a way back from Nicolas Anelka's 11th-minute strike and United now linger three points behind Arsenal at the top of the table.
"We're obviously disappointed," Giggs told MUTV, "but we have to move on now. We have a game [against Sporting Lisbon in the Champions League] on Tuesday and we have to go out and perform. We need to get back on track as soon as possible. We've done it before and we have to do it again."
Giggs struggled to put his finger on why United struggled at the Reebok Stadium, although he was quick to dismiss suggestions the Reds missed Cristiano Ronaldo and Wayne Rooney.
"We've played without them this season plenty of times and got results. I don't know what it was today. We just didn't perform the way we know we can, the way we were performing before the international break."
United forced Bolton goalkeeper Jussi Jaaskelainen into just one save during the game, despite enjoying the lion's share of possession.
"We didn't create many chances and that's disappointing," Giggs said. "We got ourselves into good positions but were lacking some composure in the final third. In tight games like this you have to punish their mistakes on capitalise on your own good play – we didn't do that."