It's indeed a low standard when Trump can keep his cool for 40 mins and people give him credit - that's the expectation, not an accomplishment.
He did OK until the election result response and the "nasty woman" comment. The "bad ombre" comment is getting a lot of run, but if that had been his only answer of controversy, he could have made inroads. Unfortunately, those 2 other responses on the election and "nasty woman" are already getting the most run not just in the media, but in the focus groups of undecided viewers. Given his need to really turn things around, I think that's the death knell to his chances.
The thing is, the undecided voters are most worried about his fitness and temperament to be president - by refusing to say he'd accept the election results (if he was worried about extraordinary circumstances like a required recount, all he had to say was "barring extraordinary circumstances, yes, I'd accept"), and the "nasty woman" comment - he basically reinforced the concerns that he'd be too impulsive and/or erratic to serve as a leader. Plus, while his stance on abortion aligns with the GOP, it's hard to see how it's going to bring in the undecided female voter under 40 (and those with daughters, over 40), other than the GOP members who are already as like-minded as he is on the subject.
It's too bad we didn't have 3 debates like last night, because it was the most on-topic discussion we saw. Kudos to the moderator, he was the most effective one of the 3 so far.