MANCHESTER: Louis Van Gaal made no secret of his disappointment at the 2-1 home defeat by Swansea with which Manchester United marked his Premier League debut.

The Dutchman told BT Sport: “We didn’t reach the level we have shown in the past matches and that is disappointing because this is the most important match. We were disappointing in defence and we are disappointed with ourselves and that’s why we lost today.

It was disappointing. We disappointed the fans and ourselves.”

He rejected a suggestion that the nature of the defeat had increased the urgency of entering the transfer market to strengthen defence because “I have already said so.”

He added: “You cannot say, because of one game, that it is [down to] the defence. I think it’s the team – how we played. We never played as a team and that’s our error.”

Garry Monk’s Swansea side took advantage of United’s unfamiliarity with playing three at the back in the first half, but once they added an extra body in defence the home side looked more comfortable.

Van Gaal revealed that he decided early on in the clash to make that tactical switch to combat what the Swans were doing.

“They made the pitch very big and then we have to press more in front and the system 4-3-3 is a better system to press the ball,” he said. “We started to do that very well and we scored a fantastic goal and then we have chances to make it 2-1 but chances is not enough, you have to take the chances. The result is what counts.”

Predecessor David Moyes’s short spell in charge at United also set under way against the same opponents this time last year. On that occasion the Red Devils left the Liberty Stadium with three points after a convincing 4-1 victory.

Earlier this week Van Gaal stressed that he wanted to get a victory to breathe confidence into Old Trafford again, but the memory of how last season descended into a seventh-placed finish should act as a cautionary tale for judging this opening-day result too harshly.

The 63-year-old said he needed to analyse the defeat because he could not fault the effort put in by his players.

“The first thing that I say is that we are not reaching our level and we have to evaluate why because they have done their utmost best,” he added.

“I cannot say they didn’t do their best because you can see in the second half they have run all the miles together but I think we have to always keep our heads up and use the second step in our process better than we have today.”