While Simon Grayson’s men had enjoyed the better of a dreadfully dull first hour they had lacked the cutting edge when it mattered most.
But skipper Tom Clarke led by example in the 62nd minute when he got on to the end of a free-kick from Chris Humphrey and side-footed coolly home from just five yards out.
The home fans might have expected a reaction from their side, who came into the game on the back of two successive away defeats, but before Coventry had had time to reorganise, they went two behind.
Seb Hines could have few complaints when he clearly brought down Preston striker Joe Garner inside the area with an awkward tackle to concede a 67th-minute penalty.
The former Watford striker kept up his impressive run by netting his fourth goal in as many games from 12 yards out.
It could have been worse for the Sky Blues, who twice had Ryan Haynes to thank for last-minute blocks in front of goal.