Gillingham mounted a spirited second-half fightback to grab a point at Highfield Road.
Former Wimbledon striker Patrick Agyemang bagged two goals after Coventry had looked home and dry.
Coventry striker Andy Morrell struck his fifth goal in five games to put the home side in charge and they should have had the points wrapped up.
Morrell struck on the half-hour to finally turn Coventry's pressure into a goal and put them in front against a weak Gills side.
Tim Sherwood's free-kick was only half-cleared and on-loan defender Dean Leacock headed into Morrell's path and the former Wrexham star fired home a low left-foot volley.
Steve Banks in the Gillingham goal got two hands to the ball but it rolled over the line just before Graham Barrett followed in to make sure.
It was a deserved lead, but it took a debut goal from new signing Stern John to put the Sky Blues firmly in charge.
Coventry had just survived a scare at the start of the second half when John Hills was played through, when they got a lucky break at the other end of the field.
Steve Staunton made a foray into the Gills area and was brought down by Nicky Southall. John stepped up the beat Banks to his left.
Coventry had dominated a poor first half and only Banks has kept them out for so long. He produced a good save to keep out a diving deader by John and then denied Morrell after a neat dummy from John had played him in.
At the other end there was little for debutant Luke Steele - on loan from Manchester United - to do. He made one save when Darren Byfield turned on the edge of the area and cracked in a right-foot shot which the young keeper tipped over the bar.
That looked to be it but Gillingham hit back in fine style with 25 minutes to go when Byfield played a neat pass to Agyemang who beat Steele with ease.
Coventry boss Peter Reid spotted his side beginning to rock and took off Barrett to bring on Patrick Suffo.
But the move didn't work. With 14 minutes remaining Sherwood was guilty of turning his back on play to appeal for a foul and his error allowed Gillingham to break away - leaving Agyemang to equalise from 15 yards out.