Out of all the possible things that can happen right now.Sakura knocking Madara out (or even hurting him in the least) is the one that won´t happen, only 3 people can hurt Juudara.They are 8th gate Guy(already out of combat),the other are 2 Naruto and Sasuke.
What will most likely happen is Obito will try to stop Madara but all will be in vain.Madara will get the other Rinnegan and the roles will be reversed, instead of Naruto and Sasuke dominating Juudara and making him feel inferior, he will now have the upper hand with increased power and put both Nardo and Sauce against the ropes.