Though the polls aren't ready, I think it will help to look at the poll numbers for 'independant' voters. Last week, Harris had an 8 point lead among independants (and she's had a 4 point national lead for a month). Anyone watching the debate saw the typical angry old man avoiding answers to questions, making false and ridiculous claims, and using the same old divisive, violent rhetoric. It's an exhausting 8-year disgraceful trend that's annoyed - I'd argue - the majority of voters. Millions of viewers unfamiliar with Harris got an introduction to her approaches, proposals, debate skills, sense of humor, and in general her ability to deal with Trump's word salads of lies. He was so nervous about his performance that he later appeared on the 'Spin Room' floor to meet journalists before going to Fox for an interview. That was a first, at least in the memories of most everyone who saw it. Trump's performance was a gift to Harris's campaign because any independant would have appreciated that Harris was the only person on the stage who has the ability to be a reliable US president. She made it crystal clear that she'd represent Americans in general, whereas Trump is obviously weak, whiney, divisive, dishonest, old, boring, crazy, stupid, disgraceful, a fraud, grifter, rapist, felon, and unable to answer questions.

Edit: here's Stewart's response, which partially notes indirectly the importance of indepentant voters: https://www.youtube.com/watch?v=KtHn59wqdBc