Inter Milan's defence of the Champions League is hanging by a thread after the Italians suffered a 5-2 thrashing at home to Schalke 04 in their quarter-final, first leg on Tuesday.
In a thrilling game Inter twice took the lead but saw their defensive frailties ruthlessly exposed and even finished with 10 men as Cristian Chivu was sent off for the second game in a row.
Dejan Stankovic, with possibly the goal of the season, and Diego Milito had both put the hosts in front.
But Joel Matip, Brazilian Edu with two, Spain legend Raul with his 70th Champions League strike and an Andrea Ranocchia own goal gave the Germans a near unassailable lead to take back to Gelsenkirchen next week.
The result continued Inter boss Leonardo's miserable run of having never won at home in the Champions League as a coach in six attempts.
"We are just really happy, we worked well as a team, everyone helping each other and you saw that in the result," said Schalke captain and goalkeeper Mauel Neuer who admitted his team would be celebrating with apple juice and mineral water to prepare for their next Bundesliga match.
"I have never experienced a team scoring five goals in a game like this. To happen at Inter is just incredible."
Inter captain Javier Zanetti wasn't quite ready to throw in the towel just yet.
"This is football, we started well in the second half and then we had a black-out," he said.
"Now we have to think about the league, we need to recover some energy and concentration.
"We're calm and serene, we'll keep going forward with our heads held high and anyway, you never know in football."
A pulsating first half began as it meant to continue with a stunning goal after just 27 seconds.
Neuer came charging out of his area to meet the ball with a crowd-pleasing flying header to clear but Stankovic, just a couple of yards inside the Germans' half, adjusted his body quickly and on the volley sent the ball staight back over the Schalke captain's head and into the gaping open goal.
Schalke were level on 17 minutes as Kyriakos Papadopoulos had a free header from a corner but although his effort was weak and Julio Cesar stopped it with his feet, the ball broke kindly to Matip to blast home from close range.
Cesar then came to Inter's rescue as he saved again with his feet when Jose Jurado met a deflected Jefferson Farfan cross full on the volley.
The hosts went back in front on 34 minutes from a lovely move as Wesley Sneijder stood the ball up to the back stick and Esteban Cambiasso put a cushioned headed back into the danger zone where Milito, for once onside, volleyed home.
But on 40 minutes Edu ran onto an inch-perfect through ball and although his initial shot was deflected, it almost deceived Cesar, who could only weakly parry allowing the Brazilian to slide in the follow-up from a tight angle.
Attacks had been on top in the first 45 minutes and they were again after the restart as Milito got in behind the Schalke backline but surprisingly failed to hit the target.
Samuel Eto'o then danced through the visiting defence but Neuer pulled off a one-handed save to deny the Cameroon captain.
And yet it was Schalke who took control as Farfan slipped in Raul, who held off Andrea Ranocchia and shot past Cesar on 53 minutes.
Four minutes after that Ranocchia inadvertently directed a Jurado cross past his own keeper as Inter started to implode.
Their task became even more complicated as Chivu received his marching orders on 62 minutes for a second booking in quick succession -- he had also been dismissed against AC Milan on Saturday.
Moments later Jurardo pinged a skimming low shot off the base of the post with Cesar beaten.
With a quarter of an hour left Farfan danced through Inter's demoralised backline and although Cesar saved, the Peru flyer shot his follow-up against Ranocchia and onto the post.
Inter didn't survive for long, though, as a few seconds later Edu curled home a killer fifth that surely renders the second leg a formality.