Chelsea defender Branislav Ivanovic feels that his side have their toughest tests of the season still to come.
The Blues thrashed Belgian side Genk 5-0 at Stamford Bridge in the UEFA Champions League on Wednesday to keep them in first place in Group E.
And, despite Manchester United and Manchester City's rivalry at the top of the Premier League, Andre Villas-Boas' side are third, just a point behind the Red Devils.
Chelsea's only defeat this season was a 3-1 loss at Old Trafford in September.
Since then, the Blues have scored 12 goals in just three Premier League matches and face Queens Park Rangers in a local derby on Sunday.
Ivanovic has been involved in nine of their 10 matches this season and scored in the midweek win in the Champions League.
He told the London Evening Standard: "Since our only defeat against Manchester United, we have more confidence and are growing as a team every game.
"Bigger tests are to come but we are ready for them.
"First we have a huge derby against QPR but the games against Arsenal and Liverpool will show how good a team we are for this season.
"We have grown up. Things are going well for us but we have to work hard to stay at this level.
"Things can always change and it is too early to look back at the results we've had so far this season. We will see where we are after the New Year."