Cahill and the return to full fitness of Michael Essien has Cech upbeat about their chances of getting back into the title reckoning.
"Cahill coming in and the return of Essien means two new players for us," he told chelseafc.com. "It was great to see Michael back because it's been really tough for him with a cruciate ligament injury, but big credit to him for coming back so soon and it's great to have him back.
"It's always good to have games to help you get match fit. It will only build up from here, you saw him come on today and it's a great moment for all the players, not just because of the type of player he is but also because it gives us more options.
"With Gary, he's obviously an international defender and you always want players like that as it improves the squad. The manager will have more choices which is important with Champions League, FA Cup and league matches."