European and Premier league champions Manchester United have to play better this season because their challengers have improved, midfielder Owen Hargreaves said on the eve of the new campaign. United, with a largely unchanged squad, launch their hunt for a hat-trick of Premier League titles against Newcastle United on Sunday and Hargreaves expects another fierce challenge from Chelsea under new manager Luiz Felipe Scolari.
"We are going to have to improve if we want to repeat the success we had last season," Hargreaves told reporters. "I think Chelsea have improved. They have signed some good players, they have got a new manager and they will be very hungry.
"They have got great, experienced players who are obviously not happy with us winning the league two years in a row so it's going to be very tough this season." Chelsea were runners-up to Alex Ferguson's United in the Premier League and lost the Champions League final to them on penalties last season.
Hargreaves said Liverpool would also be capable of closing the gap on last season's top two and was not writing off Arsenal's prospects. "Liverpool have signed some good players," said the England international, who will miss the start of the season due to his recovery from a knee problem.
"It will be interesting to see how Arsenal do with some of the players they have lost...I think it could be a tough season, but somehow Arsene Wenger seems to do the business with his young players." Hargreaves also expects greater competition in Europe following the domination of English clubs in filling three of the four semi-final berths in the Champions League last season.