Ander Herrera put Man United in front at the Liberty stadium but Swansea turned the game around thanks to goals from Ki Sung-yueng and Jonjo Shelvey.
Shelvey’s winner came after a period of sustained pressure from United, with Marcos Rojo wasting their best chance to win the match by heading over from all of three yards.
Van Gaal insists United were the better team and explained how he felt United were simply unlucky
Speaking about the clash, van Gaal said: ”Of course you can say we dominated the game but the only thing we could have done more was score more out of the chances we created. Today we were the unlucky team. I think we created enough chances. We were the dominant side in both halves.
“Conceding so quickly after opening the scoring was important. It was a throw in for Swansea and we should have been more organised. But it was a good goal by Swansea.
“Today we played well – only we forgot to score. We have to be more effective.”
With Robin van Persie misfiring, Wayne Rooney dropping deep, Radamel Falcao on the bench and James Wilson left out altogether, United look like they will continue to struggle when it comes to scoring goals.
One positive for van Gaal was the performance of Herrera who got himself on the scoresheet yet again after strikes against Preston North End and Yeovil Town.