Alonso noted that Mbappé had experienced significant viral issues the previous day and would need to be assessed closer to the game. This development is a concern for Real Madrid, as they face Red Bull Salzburg in their final group match before advancing to the quarter-finals. If Mbappé's condition doesn't improve, he may miss out on the next stage of the competition.

Gastroenteritis is a common infection that affects the gut, causing symptoms like vomiting and diarrhoea. In many cases, it can last for over two weeks. For Real Madrid, losing Mbappé would be a significant blow, as they may struggle to progress in the tournament without him.