Chelsea defender Branislav Ivanovic believes that the club face their first real test of the season when they visit Arsenal on Saturday.
The Blues currently sit top of the Premier League with four wins from five games, but they are yet to face any of the current top nine teams in the table.
"We have the next game as a very great challenge for us in the Premier League - Arsenal away. This is the first actual big game for us this season," he told Sky Sports News.
"Our performances and quality - we know how it is. But we have to show everyone, and we have to show it every game. This is the biggest challenge. I think Arsenal will be a great challenge for us, and we have to really be ready for that."
Chelsea have not won the league title since 2010.