Charlton ended a desperately disappointingly season, in which they fell out of the play-off picture, with a sparkling performance.
The icing on the cake came four minutes from time when veteran Chris Powell, making his final appearance for the club, scored only the third goal of his career three minutes after coming on as a substitute.
In a blazing start Charlton scored twice in the first 19 minutes to leave Coventry rocking but, although the Midlanders quickly pulled a goal back, they were lucky not to have been beaten by a bigger score as their defence disintegrated in the second half.
It was only Charlton's second win in 11 matches in a slump which has seen them miss out on glory, but Luke Varney put them in front after just four minutes, lobbing goalkeeper Kasper Schmeichel who completely lost his bearings as he came racing out of his goal.
Varney then set up Andy Gray for Charlton's second, back-heeling the ball into the path of his fellow striker.
Michael Mifsud, with his 17th goal of the season, gave Coventry hope but three minutes after the interval another mistake by Schmeichel presented Charlton with their third goal.
The keeper punched a cross straight into the path of Grant Basey, who fired home his first Chalrton goal despite the efforts of Elliott Ward on the line to keep the ball out.
Very little was seen of Coventry as an attacking force, although Leon Best did have a goal disallowed.
But then came Powell's swansong with the fourth goal and the cheers from the 3,000 Coventry supporters at the end when they heard their side was safe was a mighty relief after their poor performance while Charlton, playing a number of youngsters, reflected on what might have been.