A first-half Elliott Ward penalty was enough to give the Sky Blues their first win in four league games and deny QPR the chance to move closer to the top two.
The match marked Iain Dowie's first visit to Coventry since his sacking in February and the emotion of the clash gave both sides urgency from kick-off.
Coventry looked stronger in the opening exchanges, with Leon McKenzie and Ward having early chances.
QPR started to push but were dealt a blow when referee Dean Whitestone awarded a 13th minute penalty.
Freddy Eastwood had brought down a long ball on the right of the area and fed in Jay Tabb, who was caught by Mikele Leigertwood as he moved towards goal. Whitestone pointed to the spot.
Ward stepped up - fresh from missing a crucial penalty at Sheffield United in midweek - and converted, despite Radek Cerny getting a hand to the ball.
The visitors offered little response for the rest of the half, but as Coventry took slowed, Emmanuel Ledesma had a golden opportunity to level.
The City defence tried to play the Argentine offside but he timed his run well and raced through, only for his sidefooted effort to be blocked by Keiren Westwood's feet.
The momentum was carried into the second half and QPR tested Coventry's resolve.
Ward was in the right place to block a goalbound deflection in the 54th minute, before Damion Stewart blasted a decent chance over the bar a minute later.
Lee Cook also came close after his shot following a mazy run was pushed wide.
Dexter Blackstock had another good chance for QPR in the 74th, but the Sky Blues held strong and bagged their second home win of the season.