Manchester United boss Sir Alex Ferguson insists his side cannot lose a single game if they are to win their first Premiership title since 2003.
Ferguson believes if he is to rein in Chelsea and Arsenal his side must step up another level too.
"We have to make sure we are flying right from the first game of the season," said Ferguson.
"The game has changed. We are possibly starting the Premier League saying we cannot afford to lose a game."
Jose Mourinho's Chelsea lost just once - away to Manchester City - on their way to claiming the title last season with a record number of points (95).
And Arsenal were also in record-breaking form, remaining unbeaten on their way to the 2003-04 crown.
In contrast, Manchester United lost five matches last season, including the opener to Chelsea.
In the past, Ferguson has tapered his training to ensure they hit peak around Christmas but he admits he must change his tactics for the campaign ahead.
"Over the last two years, Chelsea and Arsenal have suffered an average of half a defeat a season," said Ferguson.
"In a lot of seasons in the past we have been behind at Christmas and gone by the leaders by the middle of March.
"But we couldn't do that last season and we cannot afford another slow start."