I personally thought Tim Kaine won this vice presidential debate.
Mike Pence, much like Donald Trump, seemed unprepared and on edge during the debate. I thought that both Pence and Trump were having trouble in their debates controlling their anger/emotions, and seemed to be letting their opponent get the better of them. Kaine and Clinton seem to have found that sitting back and letting the other man talk is a solid strategy.
Furthermore, Pence and Trump did not seem to be on the same page. You could tell Pence was really struggling to justify Trump's actions, and he ended up hurting himself because he was not able to give a solid stance. Kaine was giving him a hard time, and he couldn't defend himself.
I think Donald Trump and Mike Pence will, themselves, be the ones responsible for losing the election, if they keep going like this.