Stephen Hughes had been man-of-the match for the first 40 minutes, but elected to pull on the keeper's shirt.
The decision was hugely unlucky on Coventry who had dominated the first half, restricting Stoke City to a single effort on goal.
Stern John carved out the first opening on nine minutes, running on to a Steve Staunton through ball, but placing his shot inches wide.
Then Gary McSheffrey pulled the ball back for Trevor Benjamin who forced a great save from Steve Simonsen from close range.
Simonsen was in action moments later when he tipped a 20-yard McSheffrey effort round the post.
The keeper was beaten all ends up by a Hughes free-kick on the half-hour mark but Clint Hill somehow lunged to make an excellent goal-line clearance.
After the break, Coventry's poor luck - and Simonsen's amazing form - continued.
Adie Williams rose to meet a Steve Staunton cross, and headed into the path of McSheffrey who was scythed down by Dave Brammer. McSheffrey, however, hit the resultant penalty at just the right height for the keeper to thwart Coventry once more.
For all Simonsen's heroics, though, the save of the match came from the makeshift keeper at the other end, as Hughes stretched to send a Lewis Neal shot round the upright.
Stoke piled on the pressure but could not find a breakthrough and Coventry held on to claim a point that, to their jubilant support, felt like a win.