Real Madrid know the return of Robert Lewandowski to the Bayern Munich side would make what looks on paper a straightforward Champions League task a whole lot more complicated.
Madrid go into the second leg of their quarter-final at the Bernabeu on Tuesday night boasting a 2-1 lead from the away leg, leaving the Germans with a mountain to climb in the Spanish capital.
The visitors need to score at least twice to progress and, given no team has been able to stop Madrid from scoring this season and the fact Zinedine Zidane's men are averaging almost three goals a game this term, in all likelihood more than that.
But the likely return of striker Lewandowski from the shoulder injury that ruled him out of the Allianz Arena clash makes such a scenario eminently possible.
Madrid themselves will be without Gareth Bale with a calf problem picked up in the first leg, which has also made him a doubt for Sunday's heavyweight LaLiga clash with Barcelona, but the presence of Cristiano Ronaldo means he will be nothing like the loss Lewandowski was for Bayern in Munich.
The Poland striker, who has 15 goals in his last 11 club games, will face a fitness test on Monday night, but has already all but declared himself fit.
'Lewandowski is a real No 9 and a bonus for Bayern,' Madrid coach Zidane said at a press conference.
The fact is, though, that Lewandowski is key for Bayern, more so than even Ronaldo, whose two first-leg goals turned that game in Madrid's favour, is for the hosts.
He provides a focal point and cutting edge that Bayern lack without him. He did not play at Bayer Leverkusen on Saturday. His side drew 0-0.
Lewandowski trained with the team with no problems on Sunday, saying afterwards that he was 'fine'.
Also read: Late Ronaldo goal secures Real win
For Madrid the match comes five days before a Clasico which could go a long way to deciding the outcome of the title race, with the capital club boasting a three-point lead over Barca, with a game in hand.
But Zidane urged his team to first spare no effort in attempting to seal their last-four spot in Europe.
Bale has had an injury-troubled season and will not be risked against Bayern, a muscle injury now having struck after the injury surgery he had earlier in the campaign.
'He's worked hard to get back with the team and after his injury, three months off, he returned really keen,' said Zidane.
'He has some discomfort that is preventing him from being at his best and I hope he'll be back with us soon. He's not going to be with us tomorrow as we don't want to risk him.
Bayern have their domestic title all but sewn up and will take to the field in Madrid determined to turn the tie around.
'We'll go there and try to turn the tide,' said captain Philipp Lahm on the club website.
Boss Carlo Ancelotti does have concerns at the back, though, with Javi Martinez suspended following his red card in the first leg and Mats Hummels (ankle) and Jerome Boateng (thigh) face, like Lewandowski, late fitness tests.