Palermo coach Gian Piero Gasperini has slammed his former side Inter before the two clash this weekend.
The 54-year-old was only given three months before facing the sack at the Nerazzurri back in September 2011 and he believes the tactics he implemented into the side - which cost him his job - are now being embraced.
"The three-man defence is now popular and even seen at Inter. However, when I was there it was not accepted," Gasperini told reporters.
"When I left I was not angry, more upset and disappointed as I had built up some good working relationships. It is also frustrating to see that they bought [Rodrigo] Palacio a year after I had requested him."
Gasperini also said that it will be a tough test for Palermo when they travel to the San Siro to face Inter on Sunday.
He added: "We always have a tough fixture list in this league and we need to pick up points against everyone. A victory at San Siro would show that we can step up and show our quality."
Palermo currently lie in 15th position while Andrea Stramaccioni's side are in fourth place.