With fellow strugglers Northampton also claiming all three points at Dagenham & Redbridge, Wycombe are now in the bottom two and staring relegation in the face.
Lee Brown gave Rovers an early lead; Matt McClure equalised for Wycombe with his eighth goal of the season before the break but Clarkson had the last laugh, condemning the home side to just one win from their last 11 games.
A fast eighth-minute break allowed Matt Harrold to release Fabian Broghammer, who forced a sharp block from Anthony Stewart in the Wycombe defence.
Rovers broke the deadlock two minutes later, Lee Brown firing a stunning 25-yard free-kick into the top corner.
Wycombe reacted well and Sam Wood’s 18th-minute rocket was deflected behind by Tom Parkes.
McClure equalised a minute later with a spectacular back-heeled flick from Wood’s cross, which crept inside the far post to make it 1-1.
Both sides struggled for the remainder of the half, but Josh Scowen agonisingly miss-kicked the best opportunity from the edge of the box on 40 minutes.
The home side started the second half positively, and a smart turn from Scowen after 52 minutes in the middle allowed him to feed in McClure, but with the goal at his mercy his first-time effort drifted wide.
Bristol Rovers won it against the run of play in the 74th minute, making their first meaningful attack of the half count.
Wycombe’s McClure diverted a cross into the path of Clarkson who could not miss from six yards, sending the travelling Rovers fans into raptures.