John Terry believes Manchester United are already facing an uphill battle to retain their Barclays Premier League title.
The Chelsea and England captain is surprised at United's disappointing start to the new season, which has seen them fall five points behind the Blues after just four games.
He said: 'I would have expected United to have started a bit better but a lot of clubs have bought really well over the summer. Five points is a hell of a gap to have this early on.
'It's going to be difficult for United.'
Terry believes the loss of Wayne Rooney and Cristiano Ronaldo through injury and suspension, respectively, has hit United hard.
'Maybe they're missing that spark, especially with Rooney and Ronaldo out,' he said.
'They're a great counter-attacking team, always dangerous, but they're missing those two.'
And Terry warned United that Chelsea can only get better after taking 10 points out of 12 so far.
'What's encouraging for me is that we've got this gap and we haven't been playing at our best,' he said.
'By all accounts, United should have beaten Portsmouth away but they only picked up a point. Pompey deserved something against us on Saturday but they got nothing. That shows our quality.
'Over the course of a season, it's not possible to play pretty football every week and do everything right. There are going to be times when you have to win the battle first.'