A large part of RB Leipzig’s success this season has been their defence, conceding just 26 goals and thus boasting the Bundesliga's joint-best defensive record alongside Bayern. The Leipzig defence is guarded by Upamecano.
While definitely not a tiny 185 cm attacker, Upamecano is also not what you might term a great aerial force. His aerial duel percentage performance rate of 65.08 percent in this season's Bundesliga is by no way low, putting him 18th in the division.
One of his defensive game's key features is his willingness and ability to get very tight to the opposition strikers, and to be aggressive and proactive in his defensive work. In Leipzig's Champions League win over Spurs, one clear example of this strategy could be seen...
Toby Alderweireld just inside the Spurs threaded a pass through Dele Alli's foot, with Upamecano placed a few yards behind him. Upamecano put the distance between him and Alli to a close. Upamecano has engaged with Alli to get a foot to the ball from the side to dispossess him.
Upamecano is more than willing to track opponents or chase the ball into midfield areas. This strategy will lead to circumstances where he is caught up the field higher than would usually be expected by a central defender, or in wider places compared to his central starting role.
Upamecano demonstrated the potential to rebound and easily move back into action as such conditions occur, thanks in large part to his agility. Examples of these situations could be seen in Leipzig’s away draw with Wolfsburg
Wolfsburg turned to Brekalo on the left easily and stretched RB Leipzig. A first-time pass from Brekalo leaves Schlager in the Leipzig goal bearing down on Gulacsi, with Upamecano a few yards behind the forward.
Upamecano has recognized the danger and can use his pace in a limited time to make up some yards on Schlager and clear a risky situation
His technical quality on the pitch, both in terms of advancing with the pitch at his feet and playing attacking forward passes, is a key part of Upamecano 's game which sets him apart from other central defenders.
Arsenal is one of the sides most strongly linked with a move for Upamecano. A player with the attributes described in this thread will almost definitely strengthen an Arsenal defence that has shown that in the past few seasons it requires reinforcements.
To conclude this thread, Upamecano is just 21 and is still working at a high standard, would be much more developed in the future and will likely give many years of service to whichever club would pick him up.