The defender has pleaded for patience as the new arrivals blend into the Ligue 1 champions' squad and he says he still harbours hope he can make Brazil's World Cup team
The Parisiens and their two hitmen have endured a mixed start to the defence of their Ligue 1 crown, drawing their opening two games before bouncing back with a pair of wins.
Laurent Blanc's side weren't assisted with the protracted arrival of Uruguayan striker Cavani, believes Alex, who thinks it will take time for the new arrivals to gel and the performances to improve.
"Cavani arrived late and so we weren't able to work extensively with him," the 31-year-old told L'Equipe. "There hasn't been the time to train properly so he must create an understanding with Ibrahimovic, but with a little more practice it will happen.
"Many new players arrived over the summer and it takes time to make everything work. We won our last two matches, and winning is the most important thing, but we still expect better of ourselves
"We know we must improve. There is still room for improvement and we will get it right."
Despite the €32 million summer acquisition of fellow Brazilian defender Marquinhos, Alex has started all four of PSG's league games so far and welcomed the competition from his compatriot.
"Marquinhos is a player for the future but his arrival pushes us to work harder," he said. "He is a very fast player with a great sense of anticipation, just like Thiago Silva."
Alex also revealed he still holds out hope of joining both Marquinhos and Thiago Silva in the Brazil squad for next summer's World Cup.
"I hope to play for Brazil again," he added. "This is a big season, so I'll do my best and we'll see what happens."