Phil Maynard's team took the lead after only two minute when Sam Pearson ran in a try converted by Ben Russell.
Adam Armstong converted a 27th minute penalty for the Londoners, only for Ben Russell to do the same ten minutes later.
The Cov support in a crowd of 561, thought it was Coventry who would go in at half-time ahead but on the stroke of half-time, Alexander McKenzie wnet over for a try to level the game at ten points each.
Armstrong kicked a 46th minute penalty to put Barking ahead and thirteen minutes later, he increased that by another three points when he converted a penalty.
Coventry came back with a 63rd minute Matt Tabbatts try and with a minute left to play, Ben Russell scored to put Coventry in front.
Barking were awarded a penalty with seconds to go and Armstrong did the honours to condemn Coventry to a defeat.