Blues are bound to improve - Mou
Jose Mourinho has warned the Barclays Premier League that Chelsea have plenty of room for improvement this season despite their impressive start.
The Blues, who face Aston Villa on Saturday, dropped points for the first time last weekend in drawing at defending champions Manchester City.
Diego Costa, who has scored seven goals in five Premier League games, will return despite his ongoing hamstring trouble against Villa, with the Blues seeking a fifth victory in their sixth game.
"I don't go for six, seven or eight (marks) out of 10," Mourinho said.
"We have to improve in every aspect. No doubt.
"We were deadly on the counter-attack against Everton (winning 6-3), we were fantastic with the way we defended collectively against Man City.
"We've had very good periods. But, in the end, what is important is that in this moment nobody is ahead of us.
"We look down and see the other 19 teams. Nobody is on top of us."
Mourinho made nine changes for Wednesday's Capital One Cup defeat of Bolton and is likely to revert to the majority of the line-up which began at Manchester City, although Ramires is out with a groin injury.
The Blues boss insisted his fringe players impressed in midweek despite making hard work of the Sky Bet Championship strugglers in winning 2-1.
World Cup winner Andre Schurrle missed a number of opportunities.
Mourinho would not fault his performance, although he recognised the Germany forward, like the team, is not at his best yet.
The Portuguese said: "He really wanted to make an impact in that game, and his performance was really good. It was important for him to play 90 minutes.
"He was one of the guys, like the Brazilians, who reached the last stage of the World Cup, his holiday was very short.
"In this last part of the World Cup, we had players in the same position: Ramires, Willian, Oscar and Schurrle. I couldn't say 'you four, holidays, I can do without you', because I couldn't do without them.
"I need them and I need them step by step. Not one of them is in super form, like (Cesc) Fabregas, (Nemanja) Matic, (Branislav) Ivanovic. At this moment, they're not. It has to be step by step."