Ander Herrera has warned his Manchester United teammates that they "cannot go crazy" during tomorrow night's Europa League tie against rivals Liverpool at Old Trafford.

Last week's 2-0 defeat on Merseyside means that Louis van Gaal's men need to win by a three-goal margin to guarantee their place in the quarter-finals of the competition.

However, despite the need to attack, Spanish midfielder Herrera has insisted that United must also remain disciplined in their approach to the game.

"We cannot go crazy. We have a game of 45 minutes, then another game of 45 minutes," he told reporters.

"Since I've been here, we've played five times against them. We've won four. I think we have a good example of how we have to play."

The Red Devils faced the same scenario against Olympiacos in the Champions League two years ago and ended up winning the contest 3-0 thanks to a Robin van Persie hat-trick.