Liberal pundits always indulge the conceit, when opinion about Republican debates, that they know how Republicans will perceive candidate performances in a primary debate. I'm going to try to avoid that with a frank admission that I haven't the slightest ability to place myself in the shoes of a Democrat primary voter and predict accurately what they will think about how the candidates.
That said, it seems impossible to score this particular debate any other way. Lincoln Chafee's presence on stage was both pointless and creepy. Jim Webb was the only candidate on stage who made occasional substantive sense, but he spent half of his time complaining about not getting any questions. I'm still not sure what the point of Martin O'Malley's candidacy is, other than to be seen on stage licking Hillary's boots.
The only two candidates on stage who mattered were Hillary Clinton and Bernie Sanders. As between the two of them, Hillary came off (to me) as the clear winner on both style and substance. Hillary was (astonishingly) much more likeable and personable than everyone's favorite crazy socialist uncle. She had few to no cringe inducing moments. She deftly threw red meat to the base when presented with the opportunity without saying anything that would hurt her in the general.
Sanders, on the other hand, failed to land a single substantive glove on Clinton and further came off as mostly an empty (and ill fitting) suit. For all that Sanders has been talked up as a guy who has been drawing huge crowds with lengthy speeches that are chock full of wonkish policy details, Sanders was remarkably pat and cliche in virtually all his answers, frequently looked downright confused, and made his biggest impressions when agreeing with what Hillary said.
This was the first introduction many people had to Bernie Sanders, and many people tuned in to see if he presented a viable alternative to Hillary as a candidate. What they saw instead was a guy who would unquestionably be an even worse and more unlikable general election candidate than Hillary.
After the first debate, the biggest Democrat challenger I can see remaining to Hillary is Joe Biden's empty podium that they dragged offstage before the debate began.