Manchester United midfielder Michael Carrick has warned that he and his teammates could "slip up" against Shrewsbury Town in the fifth round of the FA Cup on Monday.
The Red Devils suffered a 2-1 defeat against Danish minnows FC Midtjylland in the first leg of their Europa League round-of-32 tie on Thursday.
The result has piled more pressure on the shoulders of manager Louis van Gaal, whose future will reportedly be decided after the next three games.
"We know what Monday is going to be - it has been shown many times - so, yeah, we know what to expect," the Manchester Evening News quotes Carrick as saying. "It's going to be a tough game.
"Thursday has shown that if you are not anywhere near your best then you can slip up, and we need to be ready for that.
"Football's a funny old game and it throws up different things, but we know what to expect. It is not going to be an easy game. If we are at our best then we should win the game, but it is not as easy as that."
United have lost 11 games in all competitions this season.
