Pep Guardiola warned Manchester City they must 'suffer' to stop a Karim Benzema-inspired Real Madrid and reach consecutive Champions League finals.
City are attempting to go one better after losing last year's showpiece against Chelsea.
But they must navigate La Liga leaders Real first — with Guardiola telling his players to seize the moment.
'To beat an opponent like Real Madrid, when you're playing bad, stick together, suffer together for hopefully as few minutes as possible,' said Guardiola.
'I said to the players enjoy the moment. You never know, it could be once in a lifetime.'
City beat Real over two legs in the quarter-finals two years ago but are wary of the threat Benzema poses.
The striker has scored 44 goals in 47 goals for club and country this season - including a hat-trick against Chelsea in the quarter-final.
'Benzema has scored a lot of goals - not just against Chelsea but throughout his career,' said Guardiola.
'They have fantastic players.'