Coventry further rekindled their Sky Bet Championship play-off hopes with a 2-0 victory at Rotherham.
Jamie Allen and Viktor Gyokeres struck in the second half to seal back-to-back wins for Mark Robins, who got a valuable three points at his former club.
Defeat sucks Rotherham further into the battle at the other end of the table as Matt Taylor suffered disappointment in his 250th game as a manager.
Rotherham pushed for an early opener and after seeing Jordan Hugill's header from a corner chalked off, skipper Ollie Rathbone drove just wide after latching onto a poor header from former Millers loanee Brooke Norton-Cuffy.
Coventry's first effort on goal came from midfielder Gustavo Hamer but it was easily gathered by Viktor Johansson.
Johansson was called into action again when fellow Swede Gyokeres led an attack on his own and tried to fire in at the near post.
Another chance fell the way of Rathbone on the edge of the box but this time he volleyed over the bar left-footed.
A ball into the Rotherham six-yard box by Jake Bidwell caused panic but Conor Coventry was able to clear despite coming under heavy pressure from Kasey Palmer.
Rathbone then laid on a great chance for Hugill but the striker could not direct his header beyond Ben Wilson.
Coventry took the lead after 47 minutes with their first attack of the second half. Bidwell managed to pick out Allen unmarked and he poked a shot low past Johansson.
The visitors threatened a second on the counter-attack when Gyokeres was put through by Hamer but he was just beaten to the ball by Johansson before he could get a shot away.
Rotherham tried to crank up the pressure and a succession of set-pieces eventually led to a chance falling to substitute Tariqe Fosu, but his shot dribbled harmlessly wide.
Coventry again threatened on the break and Gyokeres was put in on goal by Callum Doyle. He managed to skip past two Rotherham defenders before dragging wide of goal.
Millers manager Taylor went with three up top in a bid to net an equaliser in the final 15 minutes.
Substitutes Georgie Kelly, Tom Eaves and Conor Washington led the line but the next opportunity fell to Chiedozie Ogbene and he blasted way off target.
And Coventry's victory was sealed two minutes into stoppage time when Eaves was caught out in the middle of the park. Hamer eventually worked the ball to Gyokeres and he lashed it beyond Johansson into the bottom corner.
The managers
Rotherham's Matt Taylor:
"It started well and we should have been ahead. I can't understand why the foul has been given. It's an injustice. There has not been a collision in there. It's a frustrating one. The first-half performance was good enough. As the second half went on, when we were behind, the pressure mounted and execution let us down. They are not a team you want to be chasing the game against.
"We did not have the outlets for quality. Even in the first half, the final act was not quite there. We did not do enough in that second half. I can't think of many occasions when their backline was put under pressure. The ball was never really where we wanted it. We need to start having something to show for the performances. We were reacting rather than being proactive in that second half. We need to find a way of being competitive."
Coventry's Mark Robins:
"It's a good win because these are a difficult team to play against. They tried to win the game and were brave. First half, it looked like we were playing a third game in a week. There were too many turnovers in the game. We talked about upping the work-rate 10 per cent and how that would win us the game.
"We came out with control and impetus and got the goal that gave us a leg up in the game. I think we were in control in the second half. We defended really, really well. We controlled the game and were a lot better. The goal helped. The second goal for us was superb. It was put on a plate for him. We are delighted. It was a hard-fought game. I am delighted with the three points but the performance was particularly good."