Champions League 2020/2021 season Chelsea managed to beat Real Madrid 2-0 at Stamford Bridge so that Chelsea managed to qualify because at the Santiago Bernabeu they got a 1-1 draw based on head to head in the UCL.
This result cannot be the measure of each team's strength in the current UCL season. Many things have changed, Chelsea looks not as strong as when they played in the previous season. But I don't say Chelsea has no chance to beat Real Madrid with their current situation. I just assume Real Madrid is a little bit stronger because they have got a very useful experience after beating PSG in the previous round. Their mentality has been tested well and they know how to deal with a strong team. While Chelsea still has no experience to fight with a solid team so far.