The defender scored his first goal for the club as they beat Chelsea in the Community Shield Arsenal forward Theo Walcott labelled new team mate Sead Kolasinac an "absolute tank", saying the defender is well equipped to become an instant success in the Premier League.
Kolasinac joined Arsenal on a free transfer from Schalke in the close-season and already looks an ideal fit for the physical demands of the Premier League.
Walcott revealed the hulking Kolasinac has made a big impression with his no-holds-barred approach in training and the Gunners winger is expecting opposing forwards to get an even tougher time from the Bosnian this season. "This league is the best and I think he could be one of the best in this league".
"Honestly, he's an absolute animal", Walcott said.
"The power he's got and his pace, it's attractive to watch".
"I got him as well because of his attitude; the modern game doesn't tolerate as many weaknesses anymore as it did 20 years ago". It's lovely to watch and he's a great addition to the squad. He's going to show something different, I've seen glimpses of him in pre-season and he's going to get fitter, stronger and quicker. You've got to be patient sometimes with this formation we're playing, you play a different style of football, that's what we're learning still and we're getting better.
Cahill, now club captain following the departure of John Terry at the end of last season, is disappointed to have started in such a manner but says his side have what it takes to put it behind them.
Arsenal new boy Alexandre Lacazette has been challenged to emulate Zlatan Ibrahimovic and prove that he can get goals in England.
Arsenal face Leicester City in their opening tie on Friday at the Emirates Stadium but may be without Aaron Ramsey and Mesut Ozil due to injury.