Winger Jordan Chapell made history with the fastest goal the Devon club has ever scored, but it wasn't quite enough to beat battling Pompey at Plainmoor.
Former Sheffield United starlet Chapell hit the net after only 17 seconds with his fifth goal of the season.
But with the wind behind them in the second half, Portsmouth piled on the pressure and finally equalised through substitute Ryan Bird nine minutes from time.
Knill said: "It was a great start, but it was a long way to go at 1-0.
"We're obviously disappointed that we couldn't keep it out of our net at the end, but it was probably a fair result on the day.
"When you're in the position we're in, everyone calls it a dogfight, and the first thing you have to do then is fight. I was delighted with the players' attitude."
Knill traced Pompey's revival to the moment when new loan striker Paul McCallum, from West Ham, had to be taken off with groin trouble.
"I thought Paul excellent - every time the ball went up there, he got his head on it - and once we lost him it became more difficult for us," added Knill. "We hope we got him off before he did any serious damage."
It was Torquay's veteran striker Karl Hawley who set up Chapell's 10-yard left-foot opener and the final outcome might have been different if McCallum hadn't missed a great chance, again laid on by Hawley, just before half-time.
But Pompey cranked up the pressure with the wind behind them in the second half and both Johnny Ertl and Jed Wallace went close before Wallace crossed from the right and Bird stretched out his right boot to wrong-foot Martin Rice and poke home the equaliser in the 81st minute.
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