Inter's winless run stretched to five games after a 0-0 draw against their city rivals at the San Siro.
Champions Inter have also ceded top spot in the Italian Serie A to Napoli and have a two-goal deficit to overcome against Liverpool if they are to advance to the quarterfinals of the Champions League.
Inzaghi believes the result against Stefano Pioli's side was a fair one but says his side have lost their edge recently due to the number of games they have played.
"I think the draw was the right result," Inzaghi told Mediaset. "We are still licking our wounds after losing the Serie A derby 2-1, that looked completely different until the 75th minute [Inter led for the majority of that contest].
"I think this derby was less spectacular compared to the other two, as there was a lot at stake. The two teams were anxious and looking at the 180 minutes.
"We want to reach the Final and win another trophy [but] knowing this was our 36th game of the season, we need to regain sharpness, but we are working on it.
"We're playing a lot. Apart from one error we made playing out from the back and a Handanovic save, I don't remember other Milan chances."
