Inter coach Leonardo refused to concede the Serie A title to Milan after his side's 3-0 defeat at the San Siro last night saw them slip five points behind their city rivals.
The Brazilian endured an uncomfortable evening in his first derby in the Inter camp following his 13-year association with Milan, Rossoneri fans showing their feelings by displaying banners labelling him 'Judas'.
On the pitch, Alexandre Pato was the Milan hero with a goal in each half - the first after just 45 seconds - before Antonio Cassano completed the scoring with a late penalty as Inter's title challenge suffered a major setback.
Both sides ended the game with 10 men with Inter's Cristian Chivu sent off after 54 minutes and Cassano shown a second yellow card in stoppage time.
Leonardo has not given up the chase just yet, but admits the five-point gap will be hard to make up over the final seven games of the season.
He told www.inter.it: "I don't consider it a surrender, even if five points are a lot.
"The match was conditioned by the goal in the first minute. It upset the tactics of the game and conditioned us psychologically.
"If just one of those two chances we had at the end of the first half had gone in, we would have come out after half-time with a different attitude.
"Then, after 10 minutes of the second half came the sending-off which made it all more difficult, even if AC Milan deserved it, too.
"We didn't manage to get into our stride. Going 1-0 down in the first minute put us off our game.
"In theory we had the right formation to make up the goal we conceded, but the other episodes near the end of the first half wouldn't let us.
"However, I repeat, the battle for the Scudetto is by no means over, although five points out of a possible 21 won't be easy to make up.
"It'll be a fight to the finish because Napoli and Udinese are involved too. The team is mature enough not to worry too much about [the derby]."
Of the reception he received from the Milan fans, he said: "They showed their opinion of me and expressed a feeling. I respect that, although I don't think I've done anything wrong."
Leonardo's successor, Massimiliano Allegri, felt his Milan side were good value for their victory.
Allegri told www.acmilan.it: "I think it was a great night for the lads, for Milan and the fans, for everyone.
"My players deserved this success. I told them before the game that it would be their evening, and it was.
"We did well technically and played with good intensity.
"We played as a team, more than in the last two games, when we perhaps thought that we had already won it and as a result lost focus.
"Now we have to keep concentrated, because there are still plenty of points up for grabs.
"From Tuesday on, we'll have to focus our attention to Fiorentina [next Sunday night's game].
"I think that it takes serenity to play good games, because under excessive tension you'll commit errors. The lads did well and deserved the victory. We were focused right from the start."