(Such an interesting first post )
Next season, it is undoubtable that we will see the Dragon fight the Lion in a battle of epic proportions, in shorter terms the "Queenbowl" or "Battle of the Queens". Of course, both leaders need a champion that will lead their army into battle (Ignoring the fact Dany has 3 dragons and can just burn the entire Lannister army). The number one candidate for each side is obvious, Grey Worm for Dany and Darth Gregor Clegane representing Cersei. Now, Jaimie is still in King's Landing but seems pretty pissed at the fact Cersei burnt most of King's Landing to the ground to sit on the throne, which rules him out as the ultimate fighter for Cersei.
Enough with all the backstory, time for us to place our bets on who will win in "The Worm vs The Mountain". And in my own Noob to Thrones opinion, it will be the baby faced Grey Worm that defeats the wannabe Darth Vader. Why? Cause we already saw that Clegane can easily be defeated by someone with somewhat light armor and a spear. Sadly for the last person to actually fight Clegane with light armor and a spear, he wanted to kill him for revenge and the result was the obliteration of Oberyn Martell's entire head. Grey Worm on the other hand did not have his sister raped and murdered and butchered by The Mountain. Instead Grey Worm sees The Mountain as some guy in shiny gold armor that is really, really big. Grey Worm will be too quick, and "worm" his way out of any situation. That is unless he learned that Clegane murdered his sister and orders him to ay his name......
Of course, none of this will happen if Cersei surrenders and is given trial by combat (>_>......<_<.........)