Cahill admits busy Chelsea schedule has been tough
The Blues have played 38 games this season, their schedule including matches in midweek and at the weekend for the past two months.
Cahill said: "It is demanding because you want to go into a game feeling 100 per cent - that is your best chance to get the best result and play at your best.
"But at the minute it's impossible to feel 100 per cent fresh. It is difficult but we can't use it as an excuse.