After resurrecting the career of former leading striker Ade Akinbiyi the Burnley boss placed his faith in the ability of 27-year-old Ricketts by signing the one-time England international on loan from Leeds.
Ricketts was unlucky on 20 minutes with a shot on the turn which flashed inches wide of the post.
However, the striker didn't have long to wait before hitting the net when he calmly stepped inside his marker and stroked the ball home following good work from Micah Hyde in the 24th minute.
Plymouth should have levelled before the break as a Frank Sinclair mistake was seized upon by Nick Chadwick only for his shot to be beaten away by home keeper Brian Jensen.
The Pilgrims continued to take the game to the hosts early in the second half but without really troubling the keeper.
Boss Tony Pulis made a double change as the visitors pressed hard for an equaliser and finally began to create chances.
Jensen produced a fine save to deny David Norris at the expense of a corner and then got down smartly to his left to deny Paul Wotton a deserved equaliser.
Cotterill's team were forced to endure a long four minutes of stoppage-time before finally collecting their first win of 2006, following a dismal sequence of results which had seen the Clarets collecting only two points out of the previous 18.