Carlo Ancelotti knows better than anyone how quickly things can change at Real Madrid. 

After the sensational comeback against PSG, Madrid were euphoric. They had defeated one of Europe’s elite, humiliated an economic rival, neutralised Lionel Messi and, possibly, convinced Kylian Mbappe. They were about to win La Liga and suddenly looked contenders in the Champions League too. Three weeks later, the advantage in the league is still intact thanks to a morale-boosting win over Celta Vigo on Saturday. But Ancelotti’s credit has all but evaporated. Real are unsure if their coach can travel to the first leg of their Champions League quarter-final against Chelsea on Wednesday, after he tested COVID positive last week.