Exeter 1-0 Plymouth
Plymouth Argyle's League One relegation fears increased after James Dunne's first goal of the season gave Devon rivals Exeter all three points.
Dunne struck just seconds into the second half, smashing in an unstoppable effort from a Jamie Cureton pass.
Yala Bolasie had the visitors' best chances, but his first effort was palmed away by Arthur Krysiak and then his glancing header flashed wide.
Defeat by Southampton on Monday could now confirm Argyle's relegation.
The Pilgrims had won their last five league matches against local rivals Exeter but barely threatened this time around.
Their first shot on Krysiak's goal came midway through the second half, but Jim Paterson's effort from distance was gathered at the second attempt.
Argyle huffed and puffed in the first half and had managed to nullify an Exeter side who shaded the opening period and could have gone ahead when David Noble's shot was deflected over by Karl Duguid.
However, there was nothing they could do about Dunne's winner shortly after the break, when his shot flew past a despairing David Button in the Argyle goal.
Exeter, who are already assured of their highest league finish in 30 years, almost doubled the lead when Daniel Nardiello swerved a shot wide when well-placed.
The home side were lucky to keep a clean sheet once Argyle finally awoke from their slumbers and began to pour forward.
Firstly, Rory Fallon was correctly flagged offside after sending the ball beyond Krysiak before Bolasie tested the Grecians' resolve with his two narrow misses.
The equaliser was not forthcoming though and Argyle's failure to keep a third consecutive clean sheet leaves them second from bottom in League One.