The red card was absolutely a generous gift to Real Madrid. It made things easier for them and they completely destroyed Atalanta with their very nice performance. They finally scored a goal in the 86th minute and won 1-0. But it is still very good for Real Madrid as they had many injured players.
Without Atalanta getting a red card, it would be difficult to face Real Madrid, this early minutes Atalanta immediately played with only 10 players.
It is not surprising that during the match Real Madrid controlled the match, but because many Real Madrid players could not play because of injuries.
So Real Madrid can only score one goal through Ferland Mendy in the 86th minute when the match ends. In my opinion Atalanta is just unlucky
to experience this defeat, hopefully in the second leg there will be no more red card incidents. So the match can be more interesting.