Manchester United manager Louis van Gaal slammed the converted American football pitch his team was forced to play on Friday as they launched their US tour with a 1-0 win over Club America of Mexico.

The playing surface at CenturyLink Field, home of the NFL's Seattle Seahawks, comprised a layer of grass placed over existing astroturf -- an unstable composition that put players at risk of injury, according to van Gaal.

The threadbare surface also had several brown areas. A few hours before kick-off, a groundsman could be seen spray-painting the bare patches green.

"It was not good. It was difficult," van Gaal said of the pitch after watching his team's win.

"The first surface is artificial and then natural grass is over it. So it's always moving. So you have seen a lot of players were slipping. It's not so easy.

"And also you can get more and more injuries... it's a big concern."

Van Gaal bemoaned the relative lack of purpose-built soccer stadiums with grass pitches in the United States, and the fact that pop band One Direction had hosted a concert at the Seattle venue on Wednesday.

"In the United States, American football is more important. In England we have Old Trafford and it's only for football. It's not for entertainment. It's not for One Direction. That's the difference," van Gaal said.

"In England we live football. In the USA they live American football, baseball, basketball."

Van Gaal admitted he would rather his team had played on the artificial grass beneath the layer of turf at CenturyLink.

"Maybe my players might feel differently, but I think it is better and healthier to play on that surface than this surface," he said.

Van Gaal though had few complaints about the facilities in Seattle where United have held a training camp.

"The facilities are fantastic. Could not be better," he said. "The pitches are fantastic. We have to play football on such a pitch.

"Tonight we could not play on such a pitch and that's a pity."

United will now head to California for two games next week against the San Jose Earthquakes and Barcelona before winding up their tour against Paris Saint-Germain in Chicago.
Source: AFP