Rotherham had moved to within a win of the visitors with Tuesday night's victory over QPR in the first instalment of their hectic schedule of four games in eight days.

But the gap was restored as Leo Ostigard headed in what could prove to be a massive winner for Mark Robins' team who were promoted alongside Rotherham last season.

Coventry threatened in the very first minute with skipper Liam Kelly forcing Viktor Johansson into touching his stunning volley against the woodwork.

The visitors' attacking intent was clear and they missed two glaring chances to go ahead in a matter of seconds.

Kelly's mishit shot first fell kindly to Callum O'Hare who was denied one-on-one by Johansson before Matt Godden scooped what seemed an easier chance from the rebound over the bar.

Rotherham came into the match with 20 minutes gone and were a whisker away from the opener when Lewis Wing's effort cannoned back off the post.

Johansson again came to Rotherham's rescue as Tyler Walker got on the end of a long throw but saw his goal-bound header palmed away by the Swede.

Coventry continued to look the more likely to go in front early in the second half but were struggling to carve out a clear chance.

Paul Warne made a double change on the hour mark with two-goal Tuesday night hero Freddie Ladapo and Ryan Giles, who spent the first half of the season on loan at Coventry, tasked with injecting more energy into the Millers.

But it was Coventry who got the breakthrough in the 70th minute with Ostigard rising highest to head beyond Johansson from Matty James' free-kick.

The away side were determined to get a decisive second and threatened it through Julien Dacosta but his lashed effort was diverted wide.

Coventry had to see out a nervy six minutes of added on time but did so resolutely to secure the points.