Sir Alex Ferguson says his Manchester United players cannot rest on last weekend's Community Shield victory over neighbours Manchester City.
The Red Devils open up their title defence with an away clash with West Bromwich Albion on Sunday and Fergie expects his charges to fully focus on the first game of the new season.
"They all knew last week was the Community Shield. It was not the real stuff. That starts on Sunday," he said.
"Wembley was an occasion. There was rivalry and everyone was motivated. We have to show that in every game.
"It is going to be tough. It will be a hard campaign, it always is. We will waken up to the fact last week was a different game."