Chelsea boss Antonio Conte admits it will be "very difficult" to catch Premier League pace-setters Manchester City.
Pep Guardiola's side, who beat Chelsea 1-0 last month, have opened a commanding eight-point lead at the top after just 11 games.
Manchester United and Tottenham are the nearest chasers, while Conte's champions sit a further point back in fourth.
Conte suggested City's heavy off-season investment had made the difference in the title race.
"Manchester City are playing very well and it's very difficult to think that you can catch them because, if they continue in this way, it will be very difficult for any team to try and fight for the title," Conte said ahead of Chelsea's trip to West Brom.
"But I think the six top teams in England have to try. We have to try to fight until the end. For sure, it won't be easy because I think Manchester City are very strong.
"They were a very good team last season. This season they worked very well during the transfer market and it is a team that, after this transfer market, showed themselves to be very, very strong.
"It's very difficult now to predict who will win the title in this league, but Manchester City are having a very positive path.
"It will be very difficult for the other teams."
Chelsea's visit to West Brom on Saturday is followed by a trip to Liverpool the following weekend.