I think Fortune got it right here:
Trump arguably had his best moments in the opening section of the debate, which tends to be its most-watched portion. Drawing from his stump speech, he conjured an image of a blighted U.S., outsmarted by its trading partners and abused by its own companies. He promised, with his trademark bluster and imprecision, to get tough on those responsible at home and abroad. “We have to stop our jobs from leaving,” he said, dismissing Clinton as a member of the entrenched political class that’s presided over an economic hollowing-out.
Yet Clinton moved from the start to stick Trump in his softest spot: his business dealings. In her second answer, she explained their differing approaches to the economy as the product of their “different perspectives.” While she was raised in a middle-class family, she said, Trump started out in the real-estate business with $14 million in loans from father. Trump maintains he only received a small fraction of that amount, a key to his narrative about being self-made.
Trump took the bait, the first of several times that he allowed Clinton to provoke him with scripted digs that kept him on the defensive. She weaved into an answer about economic progress under President Obama, for example, a mention that Trump cheered the housing collapse at the time as an opportunity to turn a profit. And Trump chimed in: “That’s called business, by the way.” He deployed another self-defeating interruption as Clinton listed reasons Trump might be avoiding releasing his tax returns. “Maybe he doesn’t want the American people, all of you watching tonight, to know that he’s paid nothing in federal taxes,” Clinton said. Trump, apparently confirming the charge, blurted, “That makes me smart.”
"I think Donald just criticized me for preparing for this debate. And yes, I did. And you know what else I prepared for? I prepared to be President."
Regarding the moderator, I think PoliticsUSA got it right when they said:
Lester Holt – Holt did not allow either candidate to ramble, and where Trump was concerned, he pressed the Republican nominee on releasing his tax returns, dropped the facts on stop and frisk, and held both candidates on topic and to the clock.
There was a great deal of concern before the debate that Holt would allow Trump to run wild, or hold him to a lower standard than Hillary Clinton. The NBC Nightly News anchor was a fair moderator who relied on facts and set the standard for how moderators need to conduct themselves in future debates.
The issue of race was also brought up and Trump took some fact checking from the moderator on the Birther issue:
LESTER HOLT (MODERATOR): Mr. Trump, for five years, you perpetuated a false claim that the nation's first black president was not a natural born citizen. You questioned his legitimacy. In the last couple of weeks you acknowledged what most Americans have accepted for years, the president was born in the United States. Can you tell us what took you so long?[...]I just want to get the answer here. The birth certificate was produced in 2011. You continued to tell the story and questioned the president's legitimacy in 2012, 2013, 2014, 2015, as recently as January. So, the question is what changed your mind?DONALD TRUMP: Well, nobody was pressing it. Nobody was caring much about it. I figured you'd ask the question tonight, of course. But nobody was caring much about it, but I was the one that got him to produce the birth certificate and I think I did a good job.[...]HOLT: I'm sorry, I'm going to follow up -- I will let you respond to that, because there's a lot there, but we're talking about racial healing in this segment. What do you say to Americans --TRUMP: Well, I was very -- I say nothing. I say nothing because I was able to get him to produce it. He should have produced it a long time before, I say nothing.
In sum, Trump will retain his core supporters after tonight but he did not do himself any favors with the on-the-fence Republicans or Independents who have been trending Trump in the past several weeks. Indeed, early polls indicate that undecided voters who watched the debate trended towards Hillary by an overwhelming majority. CNN conducted a small sample of 20 such undecided voters in the key battleground state of Florida and 18 of the 20 said that after watching the debate they now support Hillary over Trump. Obviously 20 people is too small of a sample to represent the entire state of Florida, but it does tend to suggest that Hillary may have actually gained ground tonight whereas Trump likely lost it at a time where he needed those in-the-middle folks to get over the 50% mark in the key battle ground states that will ultimately decide the election.
So who do you think won?