Inter coach Rafael Benitez has plans to strengthen his squad in January after the derby defeat extended their winless streak in all competitions to four matches.
The 3-1 Champions League loss to Tottenham earlier this month has been followed by Serie A draws with Lecce and Brescia, while the derby loss left them six points adrift of the table-topping Rossoneri.
Former Liverpool and Valencia boss Benitez said: "Six points from the top is not good, but the championship is long.
"We need to regroup straight away and improve in Verona (against Chievo next weekend). It is obvious that in January we will need something, but for now we need to get a win.
"Who could arrive in the next transfer window? All the players expect someone of quality to maintain the level of the side, a side that in the past season won a lot and therefore got tired and has struggled to start again."
However, Benitez's position could be under threat after club president Massimo Moratti said of Inter's display: "I didn't really like anything, not just the build-up which was poor. We did not do enough to deserve the win.
"It would seem difficult to go on like this. I don't think we were hurt by Milan's play, it seems more to me that we didn't play."