Mazzarri added the likes of Nemanja Vidic, Pablo Daniel Osvaldo, Yann M'Vila and Gary Medel to his squad during the transfer window and a new-look Inter side have made a positive start to the new campaign.
They hammered Sassuolo 7-0 on Sunday, after holding Torino to a goalless draw in their first Serie A match of the season, and ruthlessly brushed aside Stjarnan 9-0 on aggregate to reach the group stage of the Europa League.
Inter now have Dnipro in their sights as they attempt to start their Group F campaign with a victory in Kiev on Thursday - and Mazzarri has no plans to focus solely on Serie A, as he targets domestic and European success.
"We have a squad equipped to take us forward in all competitions." said the former Napoli coach.
"We'll have a good stab at all three competitions then at the end we'll see what we've managed to achieve."
Mazzarri revealed that defenders Hugo Campagnaro or Jonathan are fully fit, but only one of the two will start on Thursday.
The game will be played at the Olympic Stadium in the capital due to the ongoing conflict in eastern Ukraine, but Mazzarri does not expect that factor to make the task any easier for his side.
"Dnipro are in great shape fitness-wise. They're a strong, aggressive side." he said.
"We always go out there to win but Ukrainian sides never make it easy for you."