Four days after surrendering a five-game unbeaten run at Derby, Rory Fallon's first-half header saw the Pilgrims register a third successive home win.
However, it took a brilliant late save from Argyle's French goalkeeper Romain Larrieu to preserve the three points.
Fallon struck in the 18th minute, after a long period of Argyle ascendancy, rising at the far post to reach Chris Clark's right-wing corner and send a looping header over goalkeeper Andy Lonergan.
The Pilgrims could not build on an impressive start, however, although Lonergan was the busier of the two goalkeepers and Pilgrims' forward Jamie Mackie three times brought the best out of the North End number one.
The home side was unchanged for the sixth successive match and were unlucky not to win an early penalty when Jay McEveley appeared to trip the industrious Mackie.
After the breakthrough, Argyle were put largely on the defensive, and were not helped by an injury to right-back Mathias Doumbe, who limped off after clashing with Jon Parkin.
Luke Summerfield cleared a shot from North End midfielder Chris Sedgwick off the line towards the end of the first half and Billy Jones sent a free header wide in the second, as the visitors piled on the pressure.
The Pilgrims were not without moments of their own, however, and Paul Gallagher saw a shot blocked on the line after a neat training-ground free-kick routine.
Mackie then brought the best out of Lonergan with a cheeky shot to the near post after Fallon had teed up his team-mate.
Preston piled forward in the dying minutes to try to salvage a draw and nearly succeeded when Ross Wallace's corner dropped for centre-back Youl Mawene.
However, Larrieu somehow got his big frame down quickly to block the powerful shot form almost point-blank range.