A second-placed finish last season has the Gunners back in the big time after a seven-year absence from the game’s premier club competition.
Mikel Arteta’s side are in pot 2 ahead of next month’s draw and could land in a group alongside heavyweights such as Barcelona, Bayern Munich, Paris Saint-Germain in pot 1.
In pot 3, AC Milan could also provide a tough test upon Arsenal’s return to the top table of European football.
The club have strengthened significantly this summer following the arrivals of Kai Havertz, Declan Rice and Jurrien Timber and Arteta has confirmed they remain open to further signings.
Martinelli believes the Gunners are ready for the challenge but insists they must prepare for the worst.
“I think we need to prepare ourselves for the worst, we need to prepare ourselves for the best teams and the whole team is doing that,” Martinelli said.
“I think we are ready for a new challenge… It’s so important [our squad depth] because we have too many games in the season and it’s going to be tough again.
“We are ready to go and it’s good to have so many options”.