Birmingham substitute DJ Campbell grabbed a second-half double to seal a convincing win and take Steve Bruce's side into second in the Championship.
Campbell came off the bench to seal Birmingham's victory
Radhi Jaidi's powerful header flew into the top corner to put the Blues ahead.
Cameron Jerome wasted two great chances for the home side, while Jay Tabb and Michael Mifsud went close for Coventry.
But the Blues were on top and Campbell showed great composure to chip in his first goal before steering home another from Mehdi Nafti's cross late on.
Birmingham manager Steve Bruce, who only picked DJ Campbell because of an injury to Andy Cole:
"I made a big mistake by leaving him out of the 16 and I had to admit that to him and apologise to him for that.
"He has brightened up training sessions since he came. He keeps knocking on the door and I'm obviously going to have to put him right in my thoughts again.
"It's unfair to label him as a super-sub, but he is very, very bright. Some people are poor when they come on and can't adjust to the pace of the game.
"DJ isn't like that. He's bright and he's lively and after the chances we missed in the first half it was great to see him get a chance and put it away with his first touch.
Coventry boss Iain Dowie says his side have to bounce back quickly:
"We have to put it right because I want a big finish to the season.
"I want us to put a real run together and I want us to be among the top two or three form sides in the division come the end.
"We were top of the form table before today's game and we want to make sure we get back up there."
Birmingham: Doyle, Kelly, Martin Taylor, Jaidi, Sadler, Larsson, Johnson, Clemence (Nafti 73), Vine, Bendtner (Muamba 82), Jerome (Campbell 62).
Subs Not Used: Maik Taylor, Danns.
Goals: Jaidi 13, Campbell 65, 78.
Coventry: Marshall, Virgo, Hawkins, Ward, Hall, Osbourne (Fadiga 64), Doyle, Hughes, Tabb (Kyle 64), Adebola, Mifsud.
Subs Not Used: Steele, Page, McKenzie.
Booked: Hughes, Doyle.
Ref: T M Kettle (Rutland).