LONDON (AFP) -- Jose Mourinho has compared Tottenham's hopes of having a positive end to the season to hanging from the balcony of a fourth-floor building after losing Son Heung-min to injury.

Already without Harry Kane for much of the remainder of the campaign, Mourinho said he does not expect Son to feature again this season after the South Korean fractured his right arm in Sunday's 3-2 win at Aston Villa.

Spurs host German side RB Leipzig in the first leg of their Champions League last 16 tie on Wednesday before facing Chelsea in a match that could prove pivotal in the dog-fight to qualify for the Champions League next season.

When Mourinho arrived at Tottenham in November, Spurs were 12 points adrift of his old club in 14th, but can move above Chelsea into fourth with victory at Stamford Bridge on Saturday.

"When we arrived we were in minus 12 floor, we got on the stairs and we started climbing. But immediately the stairs broke," said Mourinho with a characteristic colourful analogy on Tuesday.

"We were trying to find a way. Lots of effort but we were going and going.

"When we arrived on the fourth floor, where we wanted to arrive, someone took the stairs away so we are now in trouble. We are holding by our arms on the balcony."

Mourinho said Tottenham are at a crossroads in their season with the FA Cup also to fight for on top of a top-four finish in the league and Champions League honours.

"Now we have two options," he added. "To fall and die because it's the fourth floor.

"The other is to climb. We will be on that balcony fighting with everything we have."

'We miss him'

Son's absence comes as a cruel blow as he had been in a rich vein of form, scoring in the last five matches after filling in for Kane up front.

The 27-year-old suffered the injury in a robust first-minute challenge from Villa's Ezri Konsa, but still went onto score twice, including a 94th minute winner.

The club did not specify how long Son would be out -- he is due to undergo surgery later this week -- but Mourinho was pessimistic.

"I'm not going to count on him again this season," Mourinho said."

With both Kane and Son missing, Lucas Moura looks like having the burden placed on him as Mourinho discounted untested Irish youngster Troy Parrott and 19-year-old Ryan Sessegnon.

"In some periods I was worried about not having attacking options on the bench, now it's not having attacking options on the pitch," said Mourinho.

"My thoughts are that Troy Parrott is not ready and Ryan Sessegnon is not a striker."

Leipzig boss Julian Nagelsmann admitted Son's absence will aid the Germans' chances in their first ever Champions League knockout tie, but insisted it will not change his gameplan.

"It is a shame when a top player is missing from a game like this. It means there is one less great player," said Nagelsmann, who played down comparisons to Mourinho despite being labelled "baby Mourinho" early in his coaching career.

"We prepared for Tottenham in detail, it doesn't matter if Kane or Son don't play.

"For Tottenham it would be better if they play but it is better for us if they don't play." (AFP)