Schalke coach Ralf Rangnick revealed how AC Milan had taught him how to beat Inter Milan ahead of their 5-2 away win in the Champions League.
Rangnick witnessed Milan's 3-0 win over the Nerazzurri at the weekend and he found in that game the key to unlock Leonardo's troops.
"We observed them in the derby against Milan and we could see there that whoever defends in numbers against Inter has got to be good on the counter-attack," he said.
"Therefore, we intentionally played attacking football. We wanted to find the holes in their defence."
Schalke ruthlessly tore the defending champions apart and could even have scored seven as they hit the woodwork twice.
"It could have ended 5-10 or 4-8," added Rangnick. "It was a fantastic match and, for us, a marvellous evening.
"For me personally, it was the best game ever.
"If anybody had told us before the game that we would have beaten Inter by three goals, I would have said that they were crazy."
But Rangnick is not getting carried away since there are still 90 minutes left to play and Inter showed in the last round against Schalke's Bundesliga rivals Bayern Munich that they are capable of coming from behind, even away from home.
"We are not thinking of the semi-finals at all yet," he said.
"We have put ourselves into a good position, but the final step has yet to be taken.
"Before then, we have an important Bundesliga match against Wolfsburg on Saturday and we have got to focus our attentions on that game now."