The Blues came from behind to beat Reading 4-2 last night, taking an early place atop the Premier League table in the process.
However, Chelsea could only manage a sixth-place finish last season, and Cahill is keen to help them back into the title race.
"The manager stressed beforehand that we haven't been top of the league for a long time and, although it's early, it's nice to be sitting there," said Cahill.
"It is something we needed to address this season and it has been drilled into us.
"It's important that we challenge this year and we have made a good start."
Chelsea will play their third game in the space of a week when they face Newcastle United at Stamford Bridge on Saturday.