Here's the full video:
Trump won the coin flip and got to choose to go second. Matt Lauer offered a ground rule, that neither candidate should use his/her time to attack the other. Clinton broke the rule in the end, and Lauer called attention to that, both to Hillary and at the beginning of Trump's turn. She was a fool to open the door, and Trump walked right through it.
Lauer was harder on Trump, interrupting and getting harsh with him. But Trump didn't let that faze him, and compared to Hillary, who was ploddingly severe and robotic, he was very good.