Tottenham Hotspur managed to come back from the dead right at the start of their Champions League adventure last August after handing Swiss minnows Young Boys a three-goal advantage inside half an hour.
But it is asking a lot of any team to climb every mountain - and scaling a peak which requires overcoming a 4-0 deficit on Wednesday against Jose Mourinho's Real Madrid is surely beyond Harry Redknapp's men.
Holders Inter Milan too have an almost insurmountable task to keep alive their hopes of retaining the title as they travel to Gelsenkirchen trailing Schalke 5-2 from the first leg.
Real were giving Spurs the run-around at the Bernabeu even before Peter Crouch earned himself two bookings in quick succession to leave ten men chasing 11 Spanish shadows.
That much of the damage, in the shape of Crouch's early departure, was self-inflicted was bad enough.
And that a former Arsenal player, Emmanuel Adebayor, should score two of the goals only increased the hurt.
Spurs had enjoyed - for the most part - a rollercoaster of a season in the tournament on their way to the last eight.
They gifted Young Boys a 3-0 first half lead in their qualifier but pulled back to 3-2 and won the return 4-0.
They then found themselves four goals down at holders Inter Milan before a Gareth Bale hattrick at least restored some pride.
That pride knew no bounds when victory over the Italians at White Hart Lane saw the Londoners win their group and go on to knock out last 16 rivals AC Milan in Italy.
But that proved the high-water mark and now Redknapp has to hope his side will overhaul Manchester City to ensure a high enough Premier League finish to ensure another crack at the event next year.
Redknapp was defiant on Monday.
"The crowd already know that on Wednesday we will give it a hell of a go," he promised.
"We had a setback against Real Madrid, but listen, they could have beaten anybody by four if you go down to 10 men. We've still got a game to come here on Wednesday, we'll give it our best shot and who knows what could happen?"
Mourinho is determined to become the first man to coach three clubs to Champions League glory match against Tottenham but he and his players are cautious as they approach the second leg.
"It looks like we are going to be in the next round - but we still have to play the match," said Real keeper Iker Casillas, who himself is chasing a third winners medal after 2000 and 2002, the last of the meringues' nine European Cups.
"Anything can happen. A poor move by one of our players that earns a red card, well look what happened to Tottenham in the first leg. It could happen to us as well."
Casillas' former Real teammate Raul, having transferred his goalscoring exploits this season to Schalke, voiced similar caution ahead of welcoming Inter.
"We need to keep our feet on the ground and show Inter respect, because they will be looking to turn it around in Germany," said Raul, who bagged his 70th Champions League goal at San Siro.
Schalke coach Ralf Rangnick, who took over last month from the sacked Felix Magath, echoed Raul's caution in warning: "We are not in the semi-finals just yet - now we have to focus."
Inter counterpart Leonardo says he still believes.
"For me, everything is possible. I think it and so do the players, all of them," the Brazilian insisted.
Milan's ex-Bayern Munich defender Lucio is back from suspension, while Schalke are without Peru striker Jefferson Farfan, who picked up his fifth yellow card at the San Siro.