Well, according to Index he hasn't been hurt even once before Touma's punch. so i doubt that anyone can win vs him.

Reversal of vectors is default mode of the barrier around him, but it is not the only one. He can alter vectors too.

Teleportation - we don't know how exactly her power works - she might be moving stuff through extra dimensions as it was theorized before, therefore teleportation uses a vector, albeit not a 3d one. It can be reversed/altered.
The theory behind teleportation is to get away from the 3 dimensions, find his/her position in the 11th dimension, and then calculate the vectors to teleport.
source - Index wiki
I think that there is only thing that could damage Accelerator - something that it outside of his understanding(new law of physics for example. or some kind of quantum tunnelling-like power effect) -as we are aware that espers need to do precise calculations to properly apply their powers.