Andrew Johnson took his tally to 10 goals in five games to secure a place in the fourth round for Palace.

Johnson arrived at Selhurst Park this summer as part of the deal which sent last season's top scorer Clinton Morrison to Birmingham, and he is repaying the faith of manager Trevor Francis after a slow start to his Eagles career.

Palace were asleep from the kick-off, but thankfully for them so was Lee Mills, who dribbled a shot feebly past the far post from a neat set-up by Craig Hignett.

The home side then survived another early scare when Brian Kerr fired wildly over the crossbar from a right-wing Richie Partridge cross in only the third minute.

Palace punished Coventry's wastefulness in the 20th minute when visiting goalkeeper Morten Hyldgaard sliced a woeful clearance straight to Dougie Freedman.

The Scottish international fed Dele Adebola, who beat his man before floating a perfectly-weighted cross for Johnson to head home from eight yards.

Freedman should have doubled the lead three minutes later when clean through on goal - but he blazed wide of the far post.

The Eagles striker must have been feeling a niggling hamstring injury which has limited his appearances recently, because he was promptly replaced by Julian Gray.

The glaring errors continued at the other end where Mills was again guilty of a bad miss, meeting another Partridge cross weakly and slicing wide.

Mills failed to improve after half-time and was replaced by Jay Bothroyd after 55 minutes, prompting a spell of sustained pressure from City.

Hignett forced a fingertip save from Alex Kolinko with a fierce header, but Palace remained dangerous.

Johnson struck the killer blow in the 75th minute, striking a vicious low drive from 20 yards past Hyldgaard and in off the near post.

Gray underlined the hosts' superiority with a third after 88 minutes, following up fellow substitute Steve Thomson's shot which Hyldgaard could only parry.

Crystal Palace: Kolinko, Butterfield, Powell, Popovic, Granville, Mullins, Riihilahti, Derry, Adebola, Freedman, Johnson.
Subs: Michopoulos, Symons, Gray, Thomson, Black.

Coventry: Hyldgaard, Gordon, Konjic, Davenport, Caldwell, Partridge, McAllister, Safri, Kerr, Hignett, Mills.
Subs: Debec, Shaw, Eustace, Chippo, Bothroyd.

Referee: R Styles (Hampshire).