There are plenty of pieces to fall into place before that scenario is possible, with Madrid nursing a 2-1 deficit ahead of its Round of 16 return against Manchester City at Etihad Stadium next month.

The winner of the City-Madrid tie will face the victor from Lyon versus Juventus when the reformatted one-off final stages begin in Lisbon from 13 August (AEST).

Ronaldo and his team-mates are 1-0 down after the away leg against their Ligue 1 opponent.

Those teams will do battle for a spot in quarter-final one, the winner of which will take on the team to emerge from quarter-final three, which was drawn as Napoli or Barcelona versus Chelsea or Bayern Munich.

Fresh from its domestic double, Bayern is strongly placed having won 3-0 at Stamford Bridge in the initial match, although Lionel Messi and his colleagues have their encounter on a knife edge after a 1-1 draw at Stadio San Paolo.

The other quarter-finals comprise teams who have already booked spots in Lisbon.

Paris Saint-Germain overturned a first-leg deficit to knockout Borussia Dortmund in the Round of 16 and faces the similarly free-scoring Atalanta from Serie A.

The winner of that tie will take on RB Leipzig or Atletico Madrid, which overcame respective Premier League opposition in the form of Tottenham Hotspur and holder Liverpool in the previous stage.

UEFA Champions League quarter-final draw:

Real Madrid or Manchester City v Lyon or Juventus
RB Leipzig v Atletico Madrid
Napoli or Barcelona v Chelsea or Bayern Munich
Atalanta v Paris Saint-Germain

UEFA Champions League semi-final draw:

Winner QF1 v Winner QF3
Winner QF 2 v Winner QF4