Manchester City will "be in trouble" if they fail to improve on their mid-season performance levels during the last two Premier League campaigns, according to former Manchester United defender Gary Neville.
City have been tremendous in the first 10 games of the season, claiming 28 points from nine wins and a single draw, while they have also blown teams away in attack.
With 35 goals scored, they are averaging 3.5 per game and sit five points clear of nearest challengers United.
This is not an unusual position, though, for City, who have averaged 2.3 points per game in the first three months of the last two seasons, before then seeing that drop to 1.6 and 1.7, respectively, across November, December and January.
And Neville believes they will struggle to win the title yet again if they do not learn from their mistakes.
"They are at an outstandingly high level," he told Sky Sports .
"They can only stop themselves. I mention the words robustness and resilience.
"I look at the winter months and it seems like an old cliche - can you go away to Stoke and that sort of garbage - but there's a little bit more to it than that.
"If you look at Manchester City's last two seasons, one under Manuel Pellegrini and one under Guardiola, and you look at November, December and January. They probably would have won two titles in those two seasons if they'd have maintained their championship-winning level.
"If they drop to that level in November, December and January again then they'll be in trouble. Those months are tough, the toughest months; I don't care what anybody says [to the contrary].
"They're the toughest months to play football - the games, the weather, the injuries, the stockpile of fixtures, the Champions League, the Christmas period.
"Can they get through to February, March and April when the weather gets better again and it's an easier time of year to play football?
"My view is that has cost them in the last two seasons and if they can get through those three months then it could be one of the most outstanding performances. It is brilliant to watch, a great level of football."