Bradley Wright-Phillips fired Charlton in front after just six minutes on Saturday with his 20th goal of the season, but Jon Parkin equalised for Scunthorpe with a 21st-minute penalty after Rhoys Wiggins had fouled Garry Thompson in the box.
Scunthorpe, with only three defeats in their last 15 games, are five points clear of the relegation zone and Knill said: "We have found the right work ethic and if we continue to show that, then I'm sure we'll be alright.
"We have had a really tough programme in the last few weeks, but once again we have finished as the strongest team.
"I told the players at half-time they had done well to get back into the game after a slow start.
"I asked them if they could then go on and win it. I was delighted with them in the second half. Everything about their performance was there, apart from the vital goal we needed."
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