Coach Jose Mourinho said Inter Milan would have won Sunday's derby with only seven players after they overcame two sendings-off to beat AC Milan 2-0.
Inter moved nine points clear of second-placed Milan despite Wesley Sneijder's 27th-minute red card thanks to goals by Diego Milito and Goran Pandev.
Brazil defender Lucio was also sent off in the closing stages for handball, although Inter keeper Julio Cesar saved the ensuing penalty by Ronaldinho.
"We showed everything. The only way we would have lost is if we'd gone down to six," Mourinho (pictured top) said. "With seven we'd have won the same.
"Inter played a spectacular match from all points of view, tactical, physical, psychological - an incredible match."
The Portuguese coach was less happy with the officials, especially regarding Sneijder's red card for giving the referee sarcastic applause.
"I go away with a strange taste," he said. "It's your country, your championship, it's your problem, not mine.
"Today everything was done for us not to win this match.
"The referee asked if I'd be angry if one of my players clapped at me ironically. I said no, it's part of the game."
Milan coach Leonardo was not downbeat despite a defeat that landed a massive blow to his side's title ambitions.
"One game cannot establish how good you are," he said. "We have lots of possibilities. We have a game in hand. We have a good position in the standings. We are in the Champions League.
"We encountered Inter on a great night."
Milan went into the game as slight favorites even without injured defender Alessandro Nesta thanks to their strong revival from a poor start in which they lost the early season derby 4-0.
But Inter surprized them with an aggressive opening.
Sneijder, who recovered from a high temperature to make their starting XI, hit the far post with a long-range effort before blasting a good chance straight at Milan keeper Dida.
Milito took advantage of a blunder by Milan's Ignazio Abate, who headed the ball into his path when trying to cut out a cross, to give them a deserved lead.
Sneijder was shown a red card for giving the referee sarcastic applause when his teammate Lucio got booked for diving after a challenge by Massimo Ambrosini and an already intense clash became bad tempered.
Milan pressed hard after the break when substitute Clarence Seedorf had a header saved from short range. Ronaldinho came close with a shot from the edge of the box and Marco Borriello nodded a splendid David Beckham cross over the bar.