Louis van Gaal reckons reviving Manchester United's fortunes could be the hardest job of his 23-year management career.

Van Gaal has won league titles in Spain, Holland and Germany, as well as all the major cup competitions in Europe, but he is finding success hard to come by in his latest post.

After five matches, Van Gaal's United have just five points - their lowest tally at the start of a campaign since the Premier League's inception in 1992.

United lost four goals in 30 minutes as they crumbled to a 5-3 loss to Leicester last weekend, and Van Gaal's hopes of an immediate upturn in form have been hit by an injury crisis to his creaky defence.

"At this moment it is may be yes my toughest job," Van Gaal said.

"As a manager you know in advance it's a big challenge and the club is in a transition but you don't know in advance the difficult moments."

Some of the attacking play from United's Galacticos was simply stunning at Leicester last week, but the team's defensive deficiencies cost them dearly.

But Van Gaal insists United's defending has not been as bad as everyone makes out.

He said: Apart from the goals at Leicester we are defending well.

"The average is less than one per game. We are scoring a lot of goals, too. We are fifth or sixth in terms of scoring."

Asked if he was still confident of achieving the goal of a top-three finish set by the board, Van Gaal said: "Yes.

"We should have won last weekend. If we had we would have been two points off second place in the table.

"We will overcome things. The season lasts more than one competition day."