Summing it up: Clinton could have done better; Trump could have done worse.
Some turn this into an equation which Trump won...

It's more like Clinton didn't dispatch him and he didn't step off the cliff - the two expectations. But I'm guessing he didn't pick up any new votes and the exodus of Republican politicians will continue.
His loyal base will blame the Liberal media for his poor performance while trumpeting that he "won". Even though Trump spoke for more time and committed many, many more interruptions. What is wrong with those people?
Regarding optics (the facts are irrelevant), Clinton appeared far more vigorous and in command (she didn't need to attack Trump pointedly, that was probably her biggest error). She was also was mostly positive. Trump was entirely negative.