But Freddy Eastwood poached the only goal of the game from close range after 25 minutes to snatch all three points for a battling Sky Blues outfit who made much more of a contest of it after the break, and should arguably have added a second late on after a flurry of chances.
Having gone 19 league games unbeaten, it was Forest's second defeat in three and, with leaders Newcastle losing 3-0 at Derby, Billy Davies' side threw away the chance to move within a point of top spot.
But, having gone without a win in four, it is a much-needed victory for a Coventry side who have put more vital breathing space between themselves and the bottom three.
City's rearguard started in shaky fashion, with Keiren Westwood called upon to save well from Joe Garner after a quick free-kick caught his defensive line napping.
Indeed it was the visitors, playing some neat passing football, who dominated the opening 10 minutes.
Although the Sky Blues soon started to find their feet and Aron Gunnarsson sent a header over the crossbar.
Forest remained the more dangerous of the two sides in attack but it was the hosts who broke the deadlock midway through the first half.
Sammy Clingan fed Clinton Morrison with a quick set-piece on the left, he played the ball across the face of goal and Richard Wood's close-range effort was well kept out by Lee Camp but Eastwood was on hand to prod the rebound over the line.
Coventry centre-back James McPake almost sliced through his own net shortly after before Garner headed narrowly wide as Forest applied pressure in search of a quickfire equaliser.
For all of their possession and attacking endeavour, City were looking dangerous on the counter and Camp was called upon to turn Michael McIndoe's shot around a post.
And although the hosts had been on the back foot for most of the opening 45 minutes, they held firm to protect their slender advantage going into the break.
Chris Cohen's free-kick four minutes after the restart presented Guy Moussi with a great chance to level matters but he could only head wide.
Davies's charges were really putting Coventry under the cosh in the opening stages of the second half and the recalled Radoslaw Majewski was next to go close with a rasping drive from distance.
Nevertheless, the Sky Blues were still leading as the encounter approached the final quarter and Davies turned to Robert Earnshaw and David McGoldrick in a bid to force a leveller.
Referee Tony Bates then substituted himself due to injury, with female assistant Amy Fearn moving into the middle to take charge of the clash herself.
Coventry finally nullified Forest's threat as the game entered the final 15 minutes and should have grabbed a second themselves but substitute Gary Deegan and McIndoe both failed to find the net.
Yet it made no difference as the Sky Blues held on for victory.