Match ends, Coventry City 1, Scunthorpe United 2.
Coventry City's League One promotion hopes took another severe jolt as they suffered their third straight loss at home to managerless Scunthorpe United.
Tom Hopper latched onto a loose ball in the box to hammer home from 10 yards for the opener on nine minutes.
Murray Wallace then headed a 61st-minute second into the bottom corner.
Adam Armstrong's late penalty gave City hope after James Maddison was brought down, but the home side then had Romain Vincelot sent off in injury time.
After starting with last week's 3-0 win over Colchester, that makes it back-to-back victories for the Iron under joint caretaker managers Nick Daws and Andy Dawson, appointed following the sacking of former Coventry boss Mark Robins on 18 January.
The visitors could have had more in a first half littered with errors, Paddy Madden blasting wide after being given a clean run through after Peter Ramage's slip, while Luke Williams' curling effort hit the crossbar after Stephen Hunt's mishit.
Since winning 5-0 at Crewe on 2 January, Coventry have suffered an awful month, picking up just one point out of a possible 12, to fall nine behind leaders Burton Albion and six adrift of second-placed Gillingham, both of whom also lost.
Sky Blues boss Tony Mowbray told BBC Coventry & Warwickshire:
"I can't find words or excuses for the team. We need to show a lot more than that. The second half was better, but it wasn't to be and it was too little, too late at the end there.
"We've just had a good talk in there. We need to stick together and come back next week. But words are cheap. We need to do it on the grass. We've got to find a way of winning a football match pretty quickly."
Scunthorpe United caretaker manager Andy Dawson told BBC Radio Humberside:
"It was a great display. Coming to Coventry away, a massive team in this league with excellent front four players. It's a massive result for us and there are loads of positives to take from the game. Overall, a great day for us.
"In the first half we had a plan of what we wanted and what we tried to do, and I think we executed it fantastically. The only really disappointing thing was that we didn't go in maybe a goal or more in front.
"The lads listened to exactly what we tried to do, what we wanted and executed it perfectly."
- 12LorentzsonSubstituted forPhillipsat 78'minutes
- 4VincelotBooked at 88mins
- 19BigirimanaSubstituted forO'Brienat 45'minutes
- 42HuntSubstituted forRoseat 45'minutes
- 15DawsonSubstituted forKingat 82'minutes
- 7WilliamsSubstituted forClarkeat 90'minutes
- 22HopperSubstituted forMcSheffreyat 72'minutesBooked at 90mins
- James Linington
- Shots on Target
Second Half ends, Coventry City 1, Scunthorpe United 2.
Peter Ramage (Coventry City) wins a free kick in the attacking half.
Foul by Jamie Ness (Scunthorpe United).
Gary McSheffrey (Scunthorpe United) is shown the yellow card for a bad foul.
Andy Rose (Coventry City) wins a free kick on the left wing.
Foul by Gary McSheffrey (Scunthorpe United).
James Maddison (Coventry City) wins a free kick in the defensive half.
Foul by Neal Bishop (Scunthorpe United).
Foul by Jim O'Brien (Coventry City).
Neal Bishop (Scunthorpe United) wins a free kick in the defensive half.
Substitution, Scunthorpe United. Jordan Clarke replaces Luke Williams.
Second yellow card to Romain Vincelot (Coventry City) for a bad foul.
Foul by Romain Vincelot (Coventry City).
Jamie Ness (Scunthorpe United) wins a free kick in the attacking half.
Goal! Coventry City 1, Scunthorpe United 2. Adam Armstrong (Coventry City) converts the penalty with a right footed shot to the bottom right corner.
Penalty Coventry City. James Maddison draws a foul in the penalty area.
Penalty conceded by Jamie Ness (Scunthorpe United) after a foul in the penalty area.
Attempt saved. Aaron Phillips (Coventry City) left footed shot from outside the box is saved in the top centre of the goal.
Attempt blocked. James Maddison (Coventry City) right footed shot from the centre of the box is blocked.