Iain Hume`s 24th-minute opener put Phil Brown`s men ahead but the managerless Sky Blues were back on level terms in the 71st minute when substitute David Bell was on hand to sweep the ball home.
Yet North End continued to push forward and rewarded in the fourth minute of added time when substitute Ellington fired home from a corner by Hume to make it 2-1.
Preston began brightly and inside the first minute a superb cross from Ricardo Gardner was well cleared by Sky Blues defender Jordan Clarke.
The hosts continued to probe and in the eighth minute in-form winger Keith Treacy engineered the space to fire an 18-yard shot goalwards which drew a fine block by Richard Keogh.
In the 11th minute Preston fashioned their best chance so far when Gardner found the space to hit a left-foot shot from 12 yards that drew a fine parried save from Keiren Westwood.
In the 12th minute a corner from Treacy led to the former Blackburn winger hitting a 20-yard which Chris Hussey did well to block.
Moments later a shot from Gary McSheffrey drew a routine save from Preston goalkeeper Iain Turner.
Hume then volleyed wide in the 21st minute but three minutes later he was on target to put Preston ahead.
Treacy drilled in a shot from 20 yards and although Richard Keogh blocked his effort, Hume swept home from 12 yards with a left-foot shot into the bottom corner.
In the 40th minute North End midfielder Darren Carter just finished off some fine passing football with a low drive which was smartly saved low by Westwood in the visitors` goal.
North End were largely dominant in possession in the middle of the park and shortly before the break the impressive Treacy hit the crossbar with a long-range effort.
Preston continued to probe after the break as they went in search of a potentially decisive second goal.
In the 48th minute, Eddie Johnson hit a right-foot shot from 12 yards which failed to hit the target.
In the 52nd minute, Lukas Jutkiewicz hit a left-footed shot from the right side of the six-yard box which Turner saved comfortably.
Seconds later Bell came on in midfield to replace Carl Baker yet Preston should have edged further ahead.
Carter fired wide from 25 yards and with 19 minutes remaining Coventry drew level when a cross from Hussey found Bell 12 yards from goal and he fired into the net from 12 yards out.
Preston then almost restored their lead when Hume hit an overhead kick which flew over the crossbar from six yards.
Sky Blues striker Freddy Eastwood then headed over the crossbar with seven minutes remaining.
But there was still time for Ellington to rifle home a 12-yard volley from Hume's corner to hand Preston a precious victory.
Preston 2-1 Coventry: Match Report - view commentary, squad, and statictics of the game as it happened.
Source: DSG
