Steven Pressley checked into heartbreak hotel as a late own goal ensured his career as Fleetwood Town boss began in defeat.
Richard Wood could do nothing to stop the ball crossing the line in the final minute of normal time.
The former Sky Blues defender got a rogue touch after Chris Maxwell had denied sub George Thomas.
Both sides struggled to create meaningful chances in the first half - Coventry’s Jacob Murphy going closest to breaking the deadlock.
Ash Hunter made his mark for Fleetwood in the midweek win over Shrewsbury and went about more of the same after the break, twice testing Reice Charles-Cook in the Coventry goal.
Both sides had chances to snatch it , Jacob Murphy testing Chris Maxwell and then smashing the woodwork at one end, David Ball forcing another sharp save from Charles-Cook at the other.
And it was the Sky Blues who came up trumps in the last minute of normal time.
With Fleetwood flagging George Thomas found space on the edge of the box, Maxwell saving but the ball rebounding off one time Coventry defender Wood and into the net.
Pressley said: “We worked exceptionally hard on the detail during the 90 minutes and we have away very little.
“We gave away very few clear opportunities within the game.
“The starting point of any rebuilding has to be keeping more clean sheets than we have done.
“It’s only one in 14 now for the club.
“We have to show more consistency in that department.
“There’s elements we must improve on, especially our speed on the counter attack which improved in the second half.
“But in terms of the players trying to adapt to the new principles I thought they did very well.
“Games are decided on little moments.
“We had a couple of opportunities, we had a moment early in the first half when we’ve hit the post, (David) Ball has had a good chance when he’s come on too.”
The former Sky Blues boss was only appointed on Tuesday and had only Tuesday’s Johnstone’s Paint Trophy win over Shrewsbury Town as a benchmark.
“I based the selection on what I saw on Tuesday night,” he explained.
“The players deserved the opportunity to impress again.
“I like continuity in terms of team selection, I think that’s important.
“I think the players needed the opportunity to show their worth again.”