The reason why Ness won't pass the ball to Isagi.
Isagi is teaming up with Kaiser and if we think about it the way Yukimiya viewed Ness, as someone seeing a version of himself, then Ness’s awakening as the "magician" ties into his perception of both Isagi and Kaiser as the same self-serving, egoistic individuals. He ends up seeing them as selfish players willing to do whatever it takes to achieve their goals.
Right now, Isagi is a "pawn" in the game. He wants to win, but he’s also searching for an unforeseen element, something unpredictable that will shift the course of the match.
That shift could come from a source PxG doesn't expect. They assume Bastard revolves entirely around the Kaiser/Isagi duo, believing that whoever gets the ball last will decide the game. They don't expect nothing from Ness anymore, because in their heads, he's like a "cancer."
In my mind, Ness will be disgusted by this, similar to how Rin felt during the U-20 match, and finally enter his "flow." He will prove why he's the "magician" and the "heart" of Bastard Munchen, choosing neither Kaiser nor Isagi. Instead, he’ll create a new kind of magic, a play that will end the game once and for all.
Either he scores himself, which seems unlikely, or he aligns with Yukimiya, Kiyora and Kunigami to deliver the final goal, surpassing even the Guns & Roses logical and rational play with his magic.
