The Iron shipped four goals without reply to the Glovers, who went top of League One, at Glanford Park. Scunthorpe are bottom of the table.
"What we produced was not acceptable and I understand the feelings of the supporters after another home defeat," said Knill
"But the only people who can change things round are us ourselves. And the only way we can do that is by getting back out on the training$ ground and working even harder."
"We have got to defend much better as a team. We are okay when we are in possession, but when we do not have possession we do not have what it takes at the moment.
"When you look at the highlights of this game you will see we have had just as many chances as Yeovil - and some good ones as well. But at the moment we seem to have to do something exceptional to get the ball in the back of the net, and yet for the opposition it is far too easy to put the ball in ours.
"We are though only three games into the season, and though the results so far are of concern, things will look a bit different if we can get a couple of wins under our belts in the next two games."
Gary Johnson, the Yeovil boss, felt his side were deserved winners,
"When they got through us, they found they had goalkeeper Marek Stechto contend with. When we got through, we got through," he said.
"From our point of view it was a good game. We played some good football in the final third and managed to get in behind Scunthorpe quite a few times.
"It's nice to be up there at the top of the table, even if we are now there to be shot at."