One of the summer's biggest new acquisitions, striker Darwin Nunez, made it 1-0 after just four minutes.
Mohamed Salah added just ten minutes later.
But Real Madrid, who won the tournament last year after a series of incredible turnarounds, were able to make up for the deficit after double goals from Vinicius Junior.
The second goal was more or less a gift from the goalkeeper Alisson who shot the ball at his compatriot and then bounced it into the goal.
The match is in progress.