It won't just be Atletico Madrid getting a close look at Bayer Leverkusen's German international, Julian Brandt, because Real Madrid, more specifically its sports management, will be very attentive and interested in what happens on Tuesday night.
Los Blancos have long followed Brandt, a left-sided player with the skill set that they're looking for.
At just 20 years old, the reports on Brandt have all been more than complimentary, but Real's coaching team now want to check how he shapes up in demanding matches such as the double header with Diego Simeone's outfit.
Brandt is a product of the Leverkusen academy and has been part of the first team since 2014.
Runner-up in the last Olympic Games, the youngster has already made debut with Joachim Low's senior side, playing in four matches so far.
Bayern Munich have already tried twice to sign him, but the response has been negative.
For the moment, he won't consider playing for the team that commands the Bundesliga, and if he finally agrees to change, it will be to another league entirely.
Rudi Voller, Bayer Leverkusen's sports director, has publicly stated that the German club has no intention of selling the player until the summer of 2018, closing the door to a transfer during the next window.
Karl-Heinz Rummenigge, his counterpart at Bayern, won't give up easily mind.
If he wants a player, he usually gets them, as evidenced by the arrivals of Niklas Sulle and Sebastian Rudy, announced in January and who will be seen in the Bavarian city from the summer.
Real Madrid is waiting to see what happens with players like Isco or James and the search for possible substitutes - including Brandt - could accelerate over the coming weeks.
