Reading went 2-0 up but had to soak up endless pressure after Steve Sidwell's second-half sending off.
Coventry flew out of the blocks and on six minutes Brian Kerr watched an excellent volley whistle wide of the upright from 25 yards.
Sky Blues keeper Scott Shearer's first touch was to pick the ball out of the net when Reading took a fluke lead on ten minutes against the run of play.
Former City star John Salako took a free-kick wide on the right and his cross deceived everyone and found the opposite corner of the net.
The goal spurred Reading on and moments later they nearly scored a second when Dave Kitson attempted an ambitious overhead effort from James Harper's cross.
The match was ill-tempered and lively but short of real quality and chances, until Julian Joachim pulled away from Sidwell and hit a good effort just wide of the post from 20 yards.
Salako continued to torment his former club with a goal-line clearance from Calum Davenport's header on 40 minutes.
After the break, Salako continued his memorable return to Highfield Road with a delightful lofted pass to find Sidwell in space.
The midfielder fed Shaun Goater who comfortably slotted the ball past Shearer.
That was Sidwell's penultimate meaningful contribution, though, after he was sent off for a second bookable offence just before the hour.
Coventry piled on the pressure and got back into the game on 67 minutes when Davenport's header found Joachim, who headed on for Gary McSheffrey to head the ball in from close range.
However the Sky Blues could not find the equaliser that would have kept them in touch with the play-off places.