AC Milan coach Leonardo says Rino Gattuso's injury problems sparked Inter's 4-0 thrashing yesterday.
The game changed when Gattuso picked up an ankle injury, brought down Samuel Eto'o for a penalty and was sent off before half-time, all while he was waiting for a substitution.
Leonardo said: "Gattuso got hurt and had to keep coming off for treatment. It was our free kick and he had to run back and gave away this penalty.
"He was meant to come off, [Clarence] Seedorf wasn't ready, and the delay proved decisive. He is in hospital now for tests and those minutes made all the difference."
The biggest problem seemed to be psychological, as Milan visibly crumbled once Inter took the lead.
"I think there was a little uncertainty, but also a series of incidents that made it tougher for us. Gattuso was injured and struggled to get back, so the delay in preparing Seedorf due to a calf problem added up and the game changed.
"When a player is injured and gets there after his opponent, these things can happen. It was just one thing after another and it turned into a chain reaction. This penalty would never have happened if Gattuso had been fit."