Two own goals from defender Liam Kitching condemned Coventry to a 2-1 defeat at home to Cardiff that prevented them from closing the gap on the Sky Bet Championship play-off places.
Norwich's lunchtime defeat at Leicester presented the Sky Blues with a chance to close to within one point of the top six and they appeared to be on their way when Ellis Simms struck to extend his superb goalscoring run.
However, the luckless Kitching twice put the ball into his own net to give the mid-table Bluebirds their first win in three games and keep the gap between Coventry and the Canaries at four points.
The first chance of the game fell Coventry's way after six minutes when Haji Wright charged through the middle before playing in Kasey Palmer, whose effort was held by Cardiff goalkeeper Ethan Horvath.
A bright start by the Sky Blues continued with midfielder Ben Sheaf bending a superb effort from outside the area narrowly over the bar, with Horvath well beaten.
Against the run of play, Cardiff believed they should have been awarded a penalty in the 15th minute when Perry Ng went down under Jake Bidwell's challenge but referee Leigh Doughty was unmoved.
The hosts took the lead after 22 minutes when Palmer played the ball right for Milan van Ewijk and his low cross was tapped in by Simms for his 11th goal in seven games.
However, the Bluebirds drew level in bizarre fashion seven minutes later when Joe Ralls' corner caused problems, leading to Kitching slamming in the first of his own goals.
The best chance the Sky Blues had to regain the lead before half-time came when Van Ewijk pulled the ball back for Palmer, who miscued his effort wide.
Cardiff then almost completed the turnaround within 23 seconds of the restart when Josh Bowler hammered a long-range strike narrowly past the post.
An even better chance for the Bluebirds then came when Yakou Meite's pass put Karlan Grant clean through on goal, only for the striker to shoot well wide.
Having started the second half shakily, Coventry began to reassert themselves with Van Ewijk quickly sorting his feet out after Wright's pass ran his way before shooting off-target.
However, Kitching's tortuous afternoon took a further turn for the worse when Bowler's cross deflected off him and looped into the far corner past a stranded Brad Collins to gift the visitors the lead.
Coventry boss Mark Robins turned to his bench in trying to salvage the situation but going behind had clearly rocked the hosts, whose passing now lacked its earlier accuracy.
They did have the ball in the net with six minutes left when Wright headed in Sheaf's cross but the linesman's flag quickly silenced Coventry cheers as their promotion hopes took a hit.
Coventry City: Collins, Latibeaudiere (Tavares Desidérioa 68'), Thomas, Kitching, Bidwell (Dasilva 75'), Eccles (Torp 68'), Sheaf, van Ewijk, Palmer (O'Hare 75'), Wright, Simms.
Subs Not Used: Wilson, Binks, Kelly, Lusala, Andrews.
Cardiff City: Horvath, Ng, Phillips, Goutas, Collins, Ralls (Ramsey 85'), Siopis, Turnbull (Wintle 76'), Bowler (Tanner 90+3'), Grant, Méïté (O'Dowda 85').
Subs Not Used: Turner, Romeo, Wilson-Esbrand, Sawyers, Robinson.