During a small-sided game later in the session, the progress became even more apparent. Mats Hummels, the captain whose physical presence had previously been overwhelming for the young midfielder, found himself unable to simply muscle Mateo off the ball as he had in earlier sessions.
The moment came during a contested situation in midfield.
Hummels, using his considerable size and strength advantage, attempted to shield the ball while Mateo applied pressure from behind. In previous weeks, this would have been a hopeless contest the experienced defender would have easily maintained possession while Mateo was forced to wait for a mistake or rely on help from teammates.
But this time, Mateo's improved core strength and balance allowed him to maintain his position despite Hummels' physical advantages.