Paul Mariner started the game with a diamond formation before reverting to 4-4-2 following the introduction of livewire winger Noone.
Mariner said: "I think it was clear for all to see that we are still trying to get the system down. You can criticise it for lack of width but if you stay with the system the width will come.
"But we changed it after 60 minutes, tried to get some width into the game, had our best spell and they go up the other end and score.
"But that's football. I can't praise the players highly enough for their attitude and commitment.
"We just got done when we were having our best spell. I am very positive. The players have been fantastic.
"They are absolutely down in the dumps but there is no reason if they keep building on the performances of the second half at Preston and today."
Coventry City boss Chris Coleman said: "It was very important for us to get back-to-back victories, especially as we have come to Plymouth and won in their back yard.
"They are in and around us in the league. You look at this fixture and it doesn't matter what time of the year it is, where they are in the league or where you are, it's always a hard game.
"They make it very difficult for you and the conditions didn't help either.
"Once or twice this season I have sat here and not been very giving about my players but I have got to say today I thought they were tremendous. We deserved the three points, the first half we played very well and should have been ahead.
"We knew Plymouth would come at us second half, which they did. We had a few scares but overall it was a great team performance and Freddy scored again."